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Bottom of Form 1Electrolysis ICSE Class-10

Concise Chemistry Selina

Question 1

Fill in the blanks:

(a) Powdered sodium chloride (common salt) does not conduct an electric current, but it does so when ____ or when _____.

(b) Molten lead bromide conducts electricity. It is called an____. It is composed of lead ____ and bromide _____. The lead ions are ____charged and are called_____. The bromide ____ are _____ charged and are called ______.

(d) The electron releasing tendency of zinc is _____than that of copper.

(e) A solution of HCl gas in water conducts electricity because _____, but a solution of HCl gas in toluene does not conduct an electric current because_____.

(f) Pure water consists entirely of ………….. (ions/molecules).

(g) We can expect that pure water …………… (will/will not) normally conduct electricity.

(h) Electrolysis is the passage of……………. (electricity/electrons) through a liquid or a solution accompanied by a ………….. (physical/chemical) change.

Answer 1

(a) Powdered sodium chloride (common salt) does not conduct an electric current, but it does so when dissolved in water or when melted.

(b) Molten lead bromide conducts electricity .It is called an electrolyte. It is composed of lead ions and bromide ions. The lead ions are positively charged and are called cations. The bromide ions are negatively charged and are called anions.

(d) The electron releasing tendency of zinc is more than that of copper.

(e) A solution of HCl gas in water conducts electricity because it ionizes , but a solution of HCl gas in toluene does not conduct an electric current because it does not ionize in toluene.

(f) Pure water consists entirely of molecules.

(g) We can expect that pure water will not normally conduct electricity.

(h) Electrolysis is the passage of electricity through a liquid or a solution accompanied by a chemical change.

Question 2

Define the following terms:

(a) Electrolysis

(b) Non-electrolyte

(d) Weak electrolyte

Answer 2

(a) Electrolysis: It is the process of decomposition of a chemical compound in aqueous solutions or in molten state accompanied by a chemical change using direct electric current.

(b) Non-electrolyte: It is a compound which neither in solution nor in the molten state allows an electric current to pass through it.

Atoms which carry negative charge are called anions.

(d) Weak electrolyte: Electrolytes which allow small amount of electricity to flow through them and are partially dissociated in fused or aqueous solution are called weak electrolyte.

Question 3

What is the difference between:

(a) Modern explanation and Arrhenius explanation for the theory of electrolysis

(b) Electrolytic dissociation and ionization

(d) Electrolytic dissociation and thermal dissociation

(e) Strong electrolyte and weak electrolyte

Answer 3

(a) Difference between Modern explanation and Arrhenius explanation for the theory of electrolysis:

Arrhenius considered that water ionizes electrolytes but Modern theory explained that electrolytes are ionic even in solid state and their ions are held by strong electrostatic forces which make them immobile. Water renders these ions mobility by breaking the electrostatic forces.

(b) Difference between electrolytic dissociation and ionization :

Ionisation

Dissociation

1. Formation of positively or negatively charged ions from molecules which are not initially in the ionic state.

1. Separation of ions which are already present in an ionic compound.

2. Polar covalent compounds show ionization. e.g. HCl, H₂O

, NH₃etc.

1. Electrovalent compounds show dissociation. e.g. Potassium chloride , lead bromide, etc.

Cation	Anion
1. Are positively charged ions.	Are negatively charged ions.
2. Migrate to cathode during electrolysis.	Migrate to anode during electrolysis.
3. Gain electron from the cathode and get reduced to become a neutral atom.	Lose electrons to the anode and get oxidized to become a neutral atom.

(d) difference between Electrolytic dissociation and thermal dissociation:

Electrolytic dissociation is the dissociation of an electrovalent compound into ions in the fused state or in aqueous solution state.

Thermal dissociation: Reversible breakdown of a chemical compound into simpler substances by heating it. The splitting of ammonium chloride into ammonia and hydrogen chloride is an example. On cooling, they recombine to form the salt.

(e) difference between Strong Electrolytes and Weak Electrolytes.

Strong Electrolytes	Weak Electrolytes
Electrolytes which allow a large amount of electricity to flow through them.	Electrolytes which allow small amounts of electricity to flow through them.
These are good conductors of electricity.	These are poor conductors of electricity.
These almost completely dissociate in the fused or aqueous solution state.	These are partially dissociated in the fused or aqueous solution state.
These solutions contain only free mobile ions.	These solutions contain ions as well as molecules.

Question 4

Name:

(a) A salt which is a weak electrolyte

(b) A base which is a weak electrolyte

(d) A positively charged non-metallic ion

(e) The electrode at which reduction occurs

(f) A non-metallic element which is a conductor of electricity

Answer 4

(a) Sodium carbonate

(b) NH₄OH

(d) H⁺

(e) Electrode is cathode

(f) Graphite

Question 5

Electrolysis is a redox process. Explain.

Answer 5

Electrolysis is a redox process. The reaction at the cathode involves reduction of cations as they gain of electrons while the reaction at anode involves oxidation of anions as they loss of electrons to become neutral.

Example: Dissociation of sodium chloride during electrolysis.

NaCl Na⁺ + Cl^–

Cathode : Na⁺ + e- Na(reduction)

Cl^– – e^–Cl(oxidation)

Cl + Cl Cl₂

Overall reaction :2NaCl 2Na + Cl₂

Question 6

Classify the following substances under three headings:

(a) strong electrolytes

(b) weak electrolytes

Acetic acid, ammonium chloride, ammonium hydroxide, carbon tetrachloride, dilute hydrochloric acid, sodium acetate, dilute sulphuric acid.

Answer 6

(a) dilute hydrochloric acid, dilute sulphuric acid, sodium acetate

(b) acetic acid, ammonium hydroxide

Question 7

Explain why:

(a) Cu, though a good conductor of electricity, is a non-electrolyte.

(b) Solid sodium chloride does not allow electricity to pass through.

Answer 7

(a) Copper metal is a solid and has no mobile ions, whereas an electrolyte should dissociate into oppositely charged ions to conduct the electric current.

(b) In solid sodium chloride, Na⁺and Cl^– ions are not mobile to conduct the electric current.

Question 8

Choose A, B, C or D to match the descriptions

(i) to (v) below. Some letters may be repeated.

(A) non-electrolyte

(B) strong electrolyte

(D) metallic conductor

(i) Molten ionic compound

(ii) Carbon tetrachloride

(iii). An aluminium wire

(iv) A solution containing solvent molecules, solute molecules and ions formed by the dissociation of solute molecules.

(v) A sugar solution with sugar molecules and water molecules.

Answer 8

(i) Molten ionic compound – strong electrolyte

(ii) Carbon tetrachloride – non-electrolyte

(iii). Aluminium wire – metallic conductor

(iv) A solution containing solvent molecules, solute molecules and ions formed by the dissociation of solute molecules. – weak electrolyte

(v) A sugar solution with sugar molecules and water molecules. – non-electrolyte

Intext 2

Question 1

Name two substances in each case:

(a) Contain only molecules

(b) Contain only ions

Answer 1

(a) Glucose, Kerosene

(b) NaCl and NaOH

Question 2

Select the ion in each case that would get selectively discharged from the aqueous mixture of the ions listed below:

Answer 2

(a) OH^–

(b)Ag⁺

Question 3

(a) Among Zn and Cu, which would occur more readily in nature as metal and which as ion?

(b) Why cannot we store AgNO₃ solution in copper vessel?

Answer 3

(a) Zn occurs readily as ion whereas Cu occurs more readily as metal in nature.

(b) Copper is above silver in the electrochemical series and is thus more reactive than silver. So, copper displaces silver from silver nitrate. Hence, we cannot store AgNO₃ solution in copper vessel.

Cu +AgNO₃ Cu(NO₃)₂ + 2Ag

Question 4

(a) How would you change a metal like Cu into ions?

(b) How would you change Cu²⁺ions to Cu?

Answer 4

(a) By treating its salt with a more reactive metal.

(b) By supplying two electrons to Cu⁺²

Cu⁺²+ 2e^–Cu

Question 5

A solution of caustic soda (NaOH) in water or when fused, conducts an electric current. What is the similarity in these two cases?

Answer 5

In the aqueous state, the slightly negatively charged oxygen atoms of the polar water molecule exerts a pull on the positively charged sodium ions. A similar pull is exerted by the slightly charged hydrogen atoms of the water on the negatively charged chloride ions. Thus the ions become free in solution. These free ions conduct electricity.

In the molten state, the high temperatures required to melt the solid weakens the bond between the particles and the ions are set free.

Question 6

During electrolysis of an aqueous solution of sulphuric acid between platinum electrodes, two types of anions migrate towards the anode but only one of them is discharged.

(a) Name the two anions.

(b) Name the main product of the discharge of anion at the anode and write the anode reaction.

(d) Do you notice any change in colour. State why?

(e) Why this electrolysis is considered as an example of catalysis.

Answer 6

(a) Two anions are and OH^–.

(b) OH^– is discharged at anode and the main product of the discharge of OH^– is O₂

Reaction is :

OH^–OH +e^–

4OH 2H₂O + O₂

H⁺ + e^–H

H + H H₂

(d) No change in colour is observed.

(e) Dilute sulphuric acid catalyse the dissociation of water molecules into ions, hence electrolysis of acidified water is considered as an example of catalysis.

Question 7

Copper sulphate solution is electrolysed using a platinum anode. Study the diagram given alongside and answer the following questions:\

(a) Give the names of the electrodes A and B.

(b) Which electrode is the oxidising electrode?

Answer 7

(a) A = Platinum anode, B = Platinum or copper cathode

(b) A = Platinum anode

Question 8

To carry out the so-called ‘electrolysis of water’, sulphuric acid is added to water. How does the addition of sulphuric acid produce a conducting solution?

Answer 8

The addition of sulphuric acid causes dissociation of water into H⁺ ions and OH^– ions.

Question 9

Choosing only words from the following list, write down the appropriate words to fill in the blanks (i) to (v) below: Anions , anode, cathode, cations , electrode, electrolyte, nickel , voltameter.

The electroplating of an article with nickel requires an (i) ____ which must be solution containing (ii) ____ ions. The article to be plated is placed as the (iii) ____ of the cell in which the plating is carried out. The (iv) ____ of the cell is made from pure nickel. The ions that are attracted to the negative electrode and discharged are called (v) _____.

(b) When a molten ionic compound is electrolysed, the metal is always formed at …………… and the non-metal is formed at …………..

Answer 9

(a) Electrolyte

(b) Nickel

(d) Anode

(e) Cations

(b) cathode, anode

Question 10

Explain the following :

(a) A solution of cane sugar does not conduct electricity, but a solution of sodium chloride is a good conductor,

(b) Hydrochloric acid is a good conductor of electricity.

(c) During the electrolysis of an aqueous solution of NaCl, hydrogen ion is reduced at the cathode and not the sodium ion though both Na⁺ and H⁺ ions are present in the solution.

(d) On electrolysis of dilute copper (II) sulphate solution, copper is deposited at the cathode but hydrogen gas evolves there. Explain why.

(e) When a dilute aqueous solution of sodium chloride is electrolysed between platinum electrodes, hydrogen gas is evolved at the cathode but metallic sodium is not deposited. Why?

(f) Zinc can produce hydrogen on reacting with acids but copper cannot. Explain.

Answer 10

(a) Cane sugar is a compound which does not have ions even in solution and contains only molecules. Hence, it does not conduct electricity. On the other hand, sodium chloride solution contains free mobile ions and allows electric current to pass through it. This makes it a good conductor of electricity.

(b) Hydrochloric acid is a strong electrolyte and dissociates completely in aqueous solution. The solution contains free mobile ions which allow electric current to pass through it. Hence, hydrochloric acid is a good conductor of electricity.

(c) Hydrogen is placed lower in the electrochemical series and sodium is placed at a higher position. This is because H⁺ ions are discharged more easily at the cathode than Na⁺during electrolysis and gains electrons more easily.

Therefore, H⁺ ion is reduced at the cathode and not Na⁺ ion.

(d)Copper is placed below hydrogen in the activity series. Cu²⁺ on reduction is discharged as metallic copper in preference to hydrogen.

(e) Since hydrogen is much below sodium in the activity series, hydrogen is discharged at the cathode in preference to sodium.

(f)Zinc is more reactive than hydrogen, so it displaces hydrogen from acids, but copper is less reactive than hydrogen, so it does not liberate hydrogen from acids.

Exercise – 6

Question 1

Give reasons for the following:

(a) Electrolysis of molten lead bromide is considered to be a reaction in which oxidation and reduction go side by side i.e, a redox reaction.

(b) The blue colour of aqueous copper sulphate fades when it is electrolyzed using platinum electrodes.

(d) Aluminium is extracted from its oxide by electrolytic reduction and not by conventional reducing agents.

(e) The ratio of hydrogen and oxygen formed at the cathode and anode is 2:1 by volume.

(f) In the electrolysis of acidified water, dilute sulphuric acid is preferred to dilute nitric acid for acidification.

(g) Ammonia is unionized in the gaseous state but in the aqueous solution, it is a weak electrolyte.

(h) A graphite anode is preferred to other inert electrode during electrolysis of fused lead bromide.

(i) For electroplating with silver, silver nitrate is not used as electrolyte.

(j) Carbon tetrachloride is a liquid but does not conduct electricity.

(k) Potassium is not extracted by electrolysis of its aqueous salt solution.

Answer 1

(a) During electrolysis of lead bromide,

there is loss of electrons at anode by bromine and gain of electrons at cathode by lead. Thus oxidation and reduction go side by side. Therefore, it is a redox reaction.

(b) The blue colour of copper ions fades

due to decrease in Cu⁺² ions and finally the solution becomes colourless as soon as Cu⁺² ions are finished.

whereas it does not dissociate in solid state. The ions become free when lead bromide is in molten state but in the solid state the ions are not free since they are packed tightly together due to electrostatic force between them. Therefore, lead bromide undergoes electrolytic dissociation in the molten state.

(d) Aluminium has great affinity towards oxygen,

so it is not reduced by reducing agent. Therefore it is extracted from its oxide by electrolytic reduction.

(e) As per electrolytic reactions, 4H⁺¹ are needed at cathode and 4OH^– at the anode and two molecules of water are produced at the anode. Hence for every two molecules of water, two molecules of hydrogen and one molecule of oxygen are liberated at the cathode and anode respectively.

(f) This is because HNO₃ is volatile.

(g) Ammonia is a covalent compound.

Therefore, it is unionized in the gaseous state but in the aqueous solution it gives NH₄OH which is a weak electrolyte and dissociates into ions.

(h) Graphite is unaffected by the bromine vapours.

(i) Silver nitrate is not used as electrolyte for electroplating with silver because the deposition of silver will be very fast and hence not very smooth and uniform.

(j) Carbon tetrachloride is a liquid and does not conduct electricity because it is a covalent compound and there are no free ions present and contain only molecules.

(k) Potassium is not extracted from its aqueous salt solution by electrolysis as it can react with water.

Ques 2 complete:

Answer 2

Anode

Electrolyte

Cathode

Silver plating of spoon

Plate of pure clean silver

Solution of potassium

argento

cyanide

Article to be electroplated

Purification of copper

Impure copper

Solution of copper sulphate and dilute sulphuric acid

Thin strip of pure copper

Question 3

(a) Draw a labeled diagram to show how iron is electroplated with copper.

(b) Which solution is preferred as electrolyte, CuSO₄ or FeSO₄?

Answer 3

(a)

(b) CuSO₄ is preferred as an electrolyte.

(c) The copper anode continuously dissolves as ions in solution and is replaced periodically. The electrolyte dissociates into Cu⁺² ions which migrate towards the iron object taken as the cathode and are deposited as neutral copper atoms on the cathode.

Electrolyte: Aqueous solution of nickel sulphate

Dissociation: CuSO₄ Cu²⁺ + SO₄^2-

H₂O H⁺ + OH^–

Electrodes:

Cathode: Article to be electroplated

Anode: Block of pure copper

Electrode reactions:

Reaction at cathode: Cu²⁺ + 2e^–→ Cu (deposited)

Reaction at anode: Cu – 2e^–→ Cu²⁺

Question 4

Element X is a metal with a valency 2. Element Y is a non-metal with a valency 3.

(a) Write equations to show how X and Y form ions?

(b) If Y is a diatomic gas, write the equation for the direct combination of X and Y to form a compound.

(c) If the compound formed between X and Y is melted and an electric current passed through the molten compound, the element X will be obtained at the _____ and Y at the _________of the electrolytic cell.(Provide the missing words)

Answer 4

(a) X X²⁺ +2e^–,Y + 3e Y^3-

(b) Y₂ + 3X X₃Y₂

Question 5

Write two applications of electrolysis in which the anode diminishes in mass.

Answer 5

1. Electroplating of metals

2. Electrorefining of metals

Question 6

(a) What kind of particles will be found in a liquid compound which is a non- electrolyte?

(b) If HX is a weak acid, what particles will be present in its dilute solution apart from those of water?

(c) Cations are formed by ____ (loss/gain) of electrons and anions are formed by _________(loss/gain) of electrons. (Choose the correct word to fill in blank)

(d) What ions must be present in a solution used for electroplating a particular metal?

Answer 6

(a) Non-electrolyte contains molecules.

(b) Molecules of HX and H⁺ and X^– ions.

(d) The electrolyte used for the purpose must contain the ions of metal which is to be electroplated on the article.

Question 7

A strip of copper is placed in four different colourless salt solutions. They are KNO₃, AgNO₃, Zn(NO₃)₂ and Ca(NO₃)₂. Which one of the solutions will finally turn blue?

Answer 7

AgNO₃solution

Hydrogen Chloride ICSE Class-10 Concise Chemistry Selina Solutions Chapter-8

Study of Compound-A

Hydrogen Chloride ICSE Class-10 Exercise- 8

Question 1

Draw a labelled diagram for the laboratory preparation of hydrogen chloride gas and answer the following

(a) Name the acid used. Why is this particular acid preferred to other acids?

(b) Give the balanced equation for the reaction.

(d) Phosphorous penta oxide and calcium oxide are good drying agents, but they cannot be used to dry hydrogen chloride gas. Why?

(e) Why is direct absorption of HCl gas in water not feasible?

(f) What arrangement is done to dissolve HCl gas in water?

Answer 1

(a) Concentrated H₂SO₄

(b) The balanced equation for the reaction:

(d) Phosphorous pentoxide and calcium oxide are good drying agents, but they cannot be used to dry hydrogen chloride gas because they react with hydrogen chloride.

(e) Hydrogen chloride gas is highly soluble in water. Therefore, it is not collected over water.

(f) The funnel arrangement is done to dissolve HCl gas in water.

Question 2

Explain why:

(a) Anhydrous HCl is a poor conductor while aq. HCl is an excellent conductor.

(b) When the stopper of a bottle full of hydrogen chloride gas is opened there are fumes in the air.

(c) A solution of hydrogen chloride in water turns blue litmus red and conducts electricity , while a solution of the same gas in toluene:

(i) Has no effect on litmus ,and

(ii) Does not conduct electricity

(d) Thick white fumes are formed when glass rod dipped in NH₄OH is brought near the mouth of bottle full of HCl gas.

(e) Dry hydrogen chloride gas does not affect a dry strip of blue litmus paper but it turns red in the presence of drop of water.

(f) Hydrogen chloride gas is not collected over water.

Answer 2

(a) Anhydrous HCl is poor conductor due to the absence of ions in it whereas aqueous HCl is excellent conductor since it contains ions.

(b) When the stopper is opened HCl gas comes in contact with water vapors of air and gives white fumes due to the formation of hydrochloric acid.

(c) A solution of HCl in water gives hydronium ions and conducts electricity, but HCl is also soluble in dry toluene, but in that case it neither (i) turns blue litmus red (ii) nor does conducts electricity. This indicates the absence of H⁺ ions in toluene showing thereby that hydrogen chloride is a covalent compound.

(d) When ammonium hydroxide is brought near the mouth of HCl, dense white fumes are formed due to the formation of ammonium chloride.

HCl + NH₄OH —–→ NH₄Cl + H₂O

(e) Dry hydrogen chloride is not acidic whereas moist Hydrogen chloride is acidic. In presence of a drop of water HCl gas dissolves in water and forms hydrochloric acid which turns blue litmus paper red.

(f) Hydrogen chloride is not collected over water as it is highly soluble in water.

Question 3

The given set up of the figure is for preparation of an acid.

(a) Name the acid prepared by this method.

(b) Name the reactants used.

(d) What is drying agent used? Why is this drying agent chosen?

(e) What is the role of inverted funnel in the arrangement?

Answer 3

(a) Hydro chloric acid is prepared by this method.

(b) The reactants are sodium chloride and Sulphuric acid.

(c) The empty flask acts as Anti-Suction device. In case the back suction occurs the water will collect in it and will not reach the generating flask.

(d) The drying agent is Conc. Sulphuric acid. Sulphuric acid is chosen as drying agent because it does not react with HCl.

(e) The Inverted funnel :

Prevents or minimizes back suction of water.

Provides a large surface area for absorption of HCl gas.

Question 4

(a) (i) Name the experiment illustrated below.

(ii) State the colour of the water that has entered the round-bottomed flask.

(b) What property of hydrogen chloride is demonstrated when it is collected by downward delivery (Upward displacement)?

Answer 4

(a)

(i) The experiment is the fountain experiment and is used to demonstrate solubility.

(ii) The colour of the water that has entered the round-bottomed flask is red.

(b) When hydrogen chloride is collected by downward delivery or upward displacement, it shows that it is heavier than air.

Question 5

(a) Name an element which reacts with hydrogen to form a compound which is strongly acidic in water.

(b) Explain why dilute hydrochloric acid cannot be concentrated by boiling beyond 22.2%.

Answer 5

(a) Hydrogen reacts with chlorine to form hydrogen chloride.

(b) Dilute hydrochloric acid cannot be concentrated by boiling beyond 22.2% because molecules ofHCl_(g) get mixed with water vapour.

Question 6

How will you prove that Hydrochloric acid contains (i) Hydrogen (ii) Chlorine.

Write equations for the reactions.

Answer 6

We can prove that hydrochloric acid contains both hydrogen and chlorine by the following experiment.

Take a voltameter used for electrolysis of water, fitted with platinum cathode and graphite anode.

Into the voltameter pour 4 molar HCl and pass direct current.

It is seen that a colourless gas is evolved at cathode and a greenish gas is evolved at anode.

When a burning splinter is brought near a colourless gas, it bursts into flame thereby proving that it is hydrogen gas.

When moist starch iodide paper is held in the greenish yellow gas, it turns blue black, thereby proving that the gas is chlorine.

2HCl ? H₂ + Cl₂

This experiment proves that hydrochloric acid contains both hydrogen and chlorine.

Question 7

Name

(a) A Black metallic oxide which reacts with hydrochloric acid to give a coloured solution.

(b) Two colourless gases, which when mixed produce a white solid.

(d) A chloride which is soluble in excess of ammonium hydroxide.

(e) The chemical in which gold can be dissolved.

(f) the experiment which demonstrates that hydrogen chloride is soluble in water.

(g) the gas produced when chlorine water is exposed to sunlight.

Answer 7

(a) Manganese dioxide

(b) Hydrogen chloride and ammonia

(d) AgCl(Silver chloride)

(e) Aqua regia

(f) Fountain experiment

(g) Hydrogen chloride gas

Question 8

Solution A reacts with an acid B (which gives greenish yellow gas on reacting with oxidizing agents like Pb₃O₄) to give white precipitate C insoluble in nitric acid but soluble in ammonium hydroxide. Name A, B and C.

Answer 8

A is Silver nitrate

B is Hydrochloric acid

C is Silver chloride

Question 9

Complete and balance the following reactions, state whether dilute or conc. acid is used.

(a) NH₄OH + HCl

(b) NaHSO₃ + HCl

(d) Pb₃O₄ + HCl

Answer 9

(a) NH₄OH + HCl NH₄Cl + H₂O

(b) NaHSO₃ + HCl NaCl + H₂O + SO₂

(d) Pb₃O₄ + 8HCl 3PbCl₂ +4H₂O +Cl₂

Question 10

How will the action of dilute hydrochloric acid enable you to distinguish between the following:

(a) Sodium carbonate and sodium sulphite.

(b) Sodium thiosulphate and sodium sulphite.

Answer 10

(a) Sodium carbonate on treating with dil.HCl results in the formation of sodium chloride with the liberation of carbon dioxide gas.

Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂ ↑

Sodium sulphite on treating with dil.HCl results in the formation of sodium chloride with the liberation of sulphur dioxide gas.

Na₂SO₃ + 2HCl → 2NaCl + H₂O + SO₂ ↑

(b) Sodium thiosulphate reacts with dil. HCl to produce sulphur dioxide gas and precipitates yellow sulphur.

Na₂S₂O₃ + 2HCl → 2NaCl + H₂O + SO₂ + S↓

Sulphur is not precipitated when sulphites are treated with dil.HCl.

Question 11

Give three distinct tests (apart from using an indicator) you would carry out with solution of HClto illustrate the typical properties of an acid.

Answer 11

Three tests are:

HCl gas gives thick white fumes of ammonium chloride when glass rod dipped in ammonia solution is held near the vapours of the acid.

NH₃ + HCl NH₄Cl

With silver nitrate HCl gives white precipitate of silver chloride. The precipitate is insoluble in nitric acid but soluble in ammonium hydroxide.

AgNO₃ + HCl AgCl + HNO₃

A greenish yellow gas is liberated when concentrated hydrochloric acid is heated with oxidizing agent like manganese dioxide.

MnO₂ + 4HCl MnCl₂ +2H₂O + Cl₂

Question 12

MnO₂, PbO₂ and red lead react with conc. HCl acid liberates Cl₂.

What is the common property being shown by these metal oxides?

Answer 12

MnO₂, PbO₂ and red lead react with conc. HCl acid to liberate Cl₂. This shows that hydrochloric acid is oxidized to chlorine by oxidizing agents.

Question 13

State which of the two – a solution of HCl in water or in toluene -is an electrolyte. Explain.

Answer 13

When hydrogen chloride gas is dissolved in water, hydrochloric acid is formed. The covalent compound ionises in water because of its polar nature and it can conduct electricity.

Hydrogen chloride gas is soluble in toluene, but there is an absence of H₃O⁺ in toluene, so it does not ionise the gas; thus, it cannot conduct electricity.

Question 14

Convert two soluble metallic nitrates to insoluble metallic chlorides using dil. HCl

Answer 14

Conversion of metallic nitrates to insoluble metallic chlorides using dil. HCl:

_(i)

_(ii)

Question 15

Convert

Hydrochloric acid to nascent chlorine.

Answer 15

A mixture having three parts of conc. hydrochloric acid and one part of conc. nitric acid gives nascent chlorine.

Answer 15

S.No.

Substances added

Gas evolved

Odour

Calcium carbonate

Magnesium ribbon

Manganese(IV) oxide with heating

Sodium sulphide

Carbon dioxide

Hydrogen

Cl₂

Hydrogen sulphide

Odourless

Strong Pungent odour

Rotten egg

Question 16

State the composition of aqua regia. State which component is the oxidizing agent in aqua regia.

Answer 16

A mixture having three parts of conc. Hydrochloric acid and one part of conc. Nitric acid is called aqua-regia.

Nitric acid acts as oxidizing agent.

Question 17

Write an equation for the reactions of hydrochloric acid on

(a) silver nitrate solution

(b) magnesium foil

(d) zinc carbonate

(e) manganese (IV) oxide

(f) copper oxide

Answer 17

Equations for the reactions of hydrochloric acid on

(a) silver nitrate

solution

(b) magnesium foil

(d) zinc carbonate

(e) manganese (IV) oxide

(f) copper oxide

Question 18 ( Imp)

Study the flow chart and give balanced equations with conditions for the conversions A, B, C,D and E.

Answer 18

NaCl + H₂SO₄NaHSO₄ + HCl

Fe + 2HCl FeCl₂ + H₂

HCl + NH₃NH₄Cl

PbO₂ + 4HCl PbCl₂ + 2H₂O + Cl₂

Question 19

Write the balanced equations for the reaction of dilute hydrochloric acid with each of the following:

(a) Iron

(b) Sodium hydrogen carbonate

(d) magnesium sulphite

Answer 19

(a) Fe +2HCl FeCl₂ +H₂

(b) NaHCO₃ + HCl NaCl + H₂O + CO₂

(d)

Question 20

Write observation

Lead nitrate solution is mixed with dilute hydrochloric acid and heated.

Answer 20

Lead nitrate solution is mixed with dilute hydrochloric acid and heated to give a white precipitate of lead (I) chloride.

Chemical Coordination Biology Chapter-7

A. Multiple choice type

Question 1

A plant hormone related with inhibition of senescence is

(a) Ethylene

(b) ABA

(d) GA

Answer 1

(d) GA

Question 2

Apical dominance phenomenon is caused by

(a) Auxins

(b) GA

(d) ABA

Answer 2

(a) Auxins

Question 3

Which of the following hormones regulate stomatal colour?

(a) Auxins

(b) GA

(d) Cytokinins

Answer 3

(d) Cytokinins

Question 4

Auxins are abundantly produced in

(a) base of the root

(b) base of the shoot

(d) meristematic region of the shoot

Answer 4

(d) meristematic region of the shoot

Question 5

A higher concentration of ethylene is found in

(a) green banana

(b) ripe banana

(d) green apple

Answer 5

(b) ripe banana

Question 6

Common gibberellin is

(a) GA₁

(b) GA₂

(d) GA₇

Answer 6

Question 7

Stems are

(a) positively geotropic and negatively phototropic

(b) positively geotropic and positively phototropic

(d) negatively phototropic and negatively geotropic

Answer 7

Question 8

In tropic movements, plant parts move

(a) away from the stimulus

(b) towards the stimulus

(d) only towards water

Answer 8

(B) SHORT ANSWER TYPE

Question 1

Match the items in column A with those of column B.

Column A	Column B
(a) Auxin	(i) apical dominance
(b) Gibberellin	(ii) cell division
(c) Cytokinin	(iii) fruit ripening
(d) Ethylene	(iv) internodal elongation

Answer 1

Column A	Column B
(a) Auxin	(i) apical dominance
(b) Gibberellin	(iv) internodal elongation
(c) Cytokinin	(ii) cell division
(d) Ethylene	(iii) fruit ripening

Question 2

Differentiate between:

(a) Thigmotropism and geotropism

(b) Phototropism and chemotropism

Answer 2

(a) Differences between thigmotropism and geotropism:

Thigmotropism	Geotropism
Directional growth movement of a plant part in response to the touch of an object	Directional growth movement of a plant part in response to gravity
Example: Coiling of tendrils around support	Example: Growth of roots of plants in downward direction

(b) Differences between phototropism and chemotropism:

Phototropism	Chemotropism
Directional growth movement of a plant part in response to light	Directional growth movement of a plant part in response to chemicals
Example: Growth of shoots of plants in upward direction	Example: Growth of pollen tube towards female gametophyte

Question 3

How is movement in plants different from that in animals?

Answer 3

Differences between movement in plants and movement in animals:

Movement in plants	Movement in animals
It involves bending, twisting and elongation of plant parts.	It involves displacement from one place to another.
Movement is said to be non-locomotory.	Movement is said to be non-locomotory.
Plants generally move to secure support, capture food or to find water or soil nutrients.	Animals generally move to find mates, for protection from environmental changes and to capture food.
Plant movements are confined to only some plant parts.	Animal movements involve movement of the entire body.
Plant movements are often related to growth.	Animal movements are not related to growth.
No muscles are involved in plant movements.	Muscles are involved in animal movements.

Question 4

Name the stimulus which causes the following movements in plants.

phototropism, thigmotropism, hydrotropism and geotropism

Answer 4

Tropic movement	Stimulus
Phototropism	Light
Thigmotropism	Touch
Hydrotropism	Water
Geotropism	Gravity

Question 5

Name the following.

(a) Hormone that stimulates growth by cell division.

(b) Growth retarding hormone in plants.

Answer 5

(a) Cytokinin

(b) Abscisic acid

(C) LONG ANSWER TYPE

Question 1

What are tropic movements? Briefly explain various types of tropic movements in plants.

Answer 1

The directional movement of plant parts towards or away from a stimulus is known as tropic movement or tropism.

Different types of tropic movements in plants:

Tropic Movement

Description

Photo-
tropism

Movement of plant parts towards or away from light is termed phototropism.

Because shoots of most plants grow towards the source of light, it is termed positive phototropism.

Roots grow away from light and hence are negatively phototropic.

Geo-

tropism

Movement of plant organs in response to gravity is termed geotropism.

Roots are positively geotropic because they grow in the direction of gravity.

The shoot grows upwards, i.e. against gravity, and hence is negatively geotropic.

Chemo-

tropism

Movement of plant organs in response to a chemical stimulus is called chemotropism.

When plant organs grow away from the chemical response, it is called negative chemotropism.

When plant parts grow towards the chemical response, it is called positive chemotropism. The pollen tube grows towards the sugary substance secreted by the stigma of the flower.

Hydro-

tropism

Movement of plant organs in response to water is termed hydrotropism.

Roots grow towards the source of moisture and hence are positively hydrotropic.

Thigmo-

tropism

Movement of plant organs in response to stimuli caused by physical contact with solid objects is termed thigmotropism.

Weak-stemmed plants use twining stems and tendrils to climb on other plants/objects which provide them support. Hence, twining stems and tendrils are positively thigmotropic.

Question 2

List five plant growth hormones and briefly describe their roles.

Answer 2

Plant growth hormones and their roles:

Plant growth hormones	Roles
Auxins	Promote elongation and the growth of stems and roots Promote cell division in vascular cambium Auxins of the apical bud inhibit the growth of lateral buds (apical dominance)
Cytokinins	Stimulate cell division and prevent the onset of senescence in tissues Stimulate cell division Break dormancy of seeds Delay senescence of leaves and other organs Promote growth of lateral buds
Gibberellins	Enhance the longitudinal growth of the stem Cause stem elongation and leaf expansion but have no effect on roots Break dormancy of buds and tubers Cause delay in senescence Promote elongation of internodes in sugarcane
Ethylene	Inhibits the growth of lateral buds and causes apical dominance Breaks the dormancy of buds and seeds Associated with the process of ageing of plant organs such as yellowing of leaves
Abscisic acid	Induces dormancy in buds, stems and seeds Induces and maintains dormancy in many seeds Inhibits flowering in short-day plants Inhibits cell division and cell elongation

Question 3

The response of plants to gravity is known as geotropism. How are plant parts sensitive to gravity? Describe with the help of a diagram.

Answer 3

The response of plants to gravity can be observed in the laboratory when the seedlings are placed in a pot filled with moist soil.

Roots of plants show positive geotropism which means that they grow in the direction of gravity in the downward direction. This movement is good for the growth of the seedling. The roots need to grow downwards in the soil in search of water and minerals.

Shoots of plants show negative geotropism which means that they grow against the direction of gravity in the upward direction. This movement is beneficial for the elongation of the plant. The shoots need to grow upwards in the direction of sunlight so that the plant can grow in height.

Question 4

What is meant by positive and negative tropic movements in plants? Explain them by giving suitable examples.

Answer 4

Positive tropic movements in plants:

Directional movement of a plant part towards the stimulus is called positive tropic movement.

Examples:

Growth of shoots towards light, And roots towards gravity,roots towards water

Negative tropic movements in plants:

Directional movement of a plant part away from the stimulus is called negative tropic movement.

Examples:

Growth of roots away from light, the shoots upwards and away from gravity, if shoots away from water

Question 5

With the help of an experiment, prove that roots are more positively hydrotropic than geotropic.

Answer 5

Aim:

To prove that roots are more positively hydrotropic than geotropic.

Apparatus:

Wire netting or gauze, wires, moist sawdust, germinating bean seeds

Procedure:

Take a piece of wire netting or gauze and suspend it with the help of wires.

Place moist sawdust of about 1 inch on the wire netting.

Embed some germinating bean seeds in the sawdust.

Observation:

As the seeds germinate, the radicles initially grow downwards through the wire netting under the influence of gravity. However, after some time they start growing upwards towards the moist sawdust. The shoots grow upwards all the time.

Inference:

Roots grow in the direction of gravity and water. The growth of roots towards water and overcoming the force of gravity suggests that roots are positively hydrotropic than geotropic. This implies that water is a more effective stimulus than gravity.

D. STRUCTURED / APPLICATION / SKILL TYPE

Selina Solution for ICSE Class 10 Chapter-7,Chemical Coordination in plant

Question 1

The tea plants are never allowed to grow lengthwise. This is done by cutting their apical buds, a process known as pruning. In this way, tea plants get a dense growth and easy yield. Answer the following questions:

(a) Name the scientific phenomenon that is being overcome by pruning.

(b) What plant hormone is responsible for the scientific phenomenon mentioned in (a).

Answer 1

(a) Apical dominance

(b) Auxins

Question 2

The figure given below shows the stages of ripening in a banana. Answer the questions that follow:

(a) Name the plant hormone responsible for the above changes.

(b) Mention two characteristic features of this hormone.

Answer 2

(a) Ethylene

(b) Characteristic features of ethylene:

Site of synthesis:

o It is synthesised in senescent leaves and flowers, germinating seeds and ripening fruits.

Functions:

o Induces and promotes fruit ripening

o Promotes fruit ripening

Chemical Coordination Biology Chapter-7

A. Multiple choice type

Question 1

A plant hormone related with inhibition of senescence is

(a) Ethylene

(b) ABA

(d) GA

Answer 1

(d) GA

Question 2

Apical dominance phenomenon is caused by

(a) Auxins

(b) GA

(d) ABA

Answer 2

(a) Auxins

Question 3

Which of the following hormones regulate stomatal colour?

(a) Auxins

(b) GA

(d) Cytokinins

Answer 3

(d) Cytokinins

Question 4

Auxins are abundantly produced in

(a) base of the root

(b) base of the shoot

(d) meristematic region of the shoot

Answer 4

(d) meristematic region of the shoot

Question 5

A higher concentration of ethylene is found in

(a) green banana

(b) ripe banana

(d) green apple

Answer 5

(b) ripe banana

Question 6

Common gibberellin is

(a) GA₁

(b) GA₂

(d) GA₇

Answer 6

Question 7

Stems are

(a) positively geotropic and negatively phototropic

(b) positively geotropic and positively phototropic

(d) negatively phototropic and negatively geotropic

Answer 7

Question 8

In tropic movements, plant parts move

(a) away from the stimulus

(b) towards the stimulus

(d) only towards water

Answer 8

(B) SHORT ANSWER TYPE

Chemical Coordination in Plant ,Chapter 7

Question 1

Match the items in column A with those of column B.

Column A	Column B
(a) Auxin	(i) apical dominance
(b) Gibberellin	(ii) cell division
(c) Cytokinin	(iii) fruit ripening
(d) Ethylene	(iv) internodal elongation

Answer 1

Column A	Column B
(a) Auxin	(i) apical dominance
(b) Gibberellin	(iv) internodal elongation
(c) Cytokinin	(ii) cell division
(d) Ethylene	(iii) fruit ripening

Question 2

Differentiate between:

(a) Thigmotropism and geotropism

(b) Phototropism and chemotropism

Answer 2

(a) Differences between thigmotropism and geotropism:

Thigmotropism	Geotropism
Directional growth movement of a plant part in response to the touch of an object	Directional growth movement of a plant part in response to gravity
Example: Coiling of tendrils around support	Example: Growth of roots of plants in downward direction

(b) Differences between phototropism and chemotropism:

Phototropism	Chemotropism
Directional growth movement of a plant part in response to light	Directional growth movement of a plant part in response to chemicals
Example: Growth of shoots of plants in upward direction	Example: Growth of pollen tube towards female gametophyte

Question 3

How is movement in plants different from that in animals?

Answer 3

Differences between movement in plants and movement in animals:

Movement in plants	Movement in animals
It involves bending, twisting and elongation of plant parts.	It involves displacement from one place to another.
Movement is said to be non-locomotory.	Movement is said to be non-locomotory.
Plants generally move to secure support, capture food or to find water or soil nutrients.	Animals generally move to find mates, for protection from environmental changes and to capture food.
Plant movements are confined to only some plant parts.	Animal movements involve movement of the entire body.
Plant movements are often related to growth.	Animal movements are not related to growth.
No muscles are involved in plant movements.	Muscles are involved in animal movements.

Question 4

Name the stimulus which causes the following movements in plants.

phototropism, thigmotropism, hydrotropism and geotropism

Answer 4

Tropic movement	Stimulus
Phototropism	Light
Thigmotropism	Touch
Hydrotropism	Water
Geotropism	Gravity

Question 5

Name the following.

(a) Hormone that stimulates growth by cell division.

(b) Growth retarding hormone in plants.

Answer 5

(a) Cytokinin

(b) Abscisic acid

(C) LONG ANSWER TYPE

Chapter-7 Chemical Coordination In Plant

Question 1

What are tropic movements? Briefly explain various types of tropic movements in plants.

Answer 1

The directional movement of plant parts towards or away from a stimulus is known as tropic movement or tropism.

Different types of tropic movements in plants:

Tropic Movement

Description

Photo-
tropism

Movement of plant parts towards or away from light is termed phototropism.

Because shoots of most plants grow towards the source of light, it is termed positive phototropism.

Roots grow away from light and hence are negatively phototropic.

Geo-

tropism

Movement of plant organs in response to gravity is termed geotropism.

Roots are positively geotropic because they grow in the direction of gravity.

The shoot grows upwards, i.e. against gravity, and hence is negatively geotropic.

Chemo-

tropism

Movement of plant organs in response to a chemical stimulus is called chemotropism.

When plant organs grow away from the chemical response, it is called negative chemotropism.

When plant parts grow towards the chemical response, it is called positive chemotropism. The pollen tube grows towards the sugary substance secreted by the stigma of the flower.

Hydro-

tropism

Movement of plant organs in response to water is termed hydrotropism.

Roots grow towards the source of moisture and hence are positively hydrotropic.

Thigmo-

tropism

Movement of plant organs in response to stimuli caused by physical contact with solid objects is termed thigmotropism.

Weak-stemmed plants use twining stems and tendrils to climb on other plants/objects which provide them support. Hence, twining stems and tendrils are positively thigmotropic.

Question 2

List five plant growth hormones and briefly describe their roles.

Answer 2

Plant growth hormones and their roles:

Plant growth hormones	Roles
Auxins	Promote elongation and the growth of stems and roots Promote cell division in vascular cambium Auxins of the apical bud inhibit the growth of lateral buds (apical dominance)
Cytokinins	Stimulate cell division and prevent the onset of senescence in tissues Stimulate cell division Break dormancy of seeds Delay senescence of leaves and other organs Promote growth of lateral buds
Gibberellins	Enhance the longitudinal growth of the stem Cause stem elongation and leaf expansion but have no effect on roots Break dormancy of buds and tubers Cause delay in senescence Promote elongation of internodes in sugarcane
Ethylene	Inhibits the growth of lateral buds and causes apical dominance Breaks the dormancy of buds and seeds Associated with the process of ageing of plant organs such as yellowing of leaves
Abscisic acid	Induces dormancy in buds, stems and seeds Induces and maintains dormancy in many seeds Inhibits flowering in short-day plants Inhibits cell division and cell elongation

Question 3

The response of plants to gravity is known as geotropism. How are plant parts sensitive to gravity? Describe with the help of a diagram.

Answer 3

The response of plants to gravity can be observed in the laboratory when the seedlings are placed in a pot filled with moist soil.

Question 4

What is meant by positive and negative tropic movements in plants? Explain them by giving suitable examples.

Answer 4

Positive tropic movements in plants:

Directional movement of a plant part towards the stimulus is called positive tropic movement.

Examples:

Growth of shoots towards light, And roots towards gravity,roots towards water

Negative tropic movements in plants:

Directional movement of a plant part away from the stimulus is called negative tropic movement.

Examples:

Growth of roots away from light, the shoots upwards and away from gravity, if shoots away from water

Question 5

With the help of an experiment, prove that roots are more positively hydrotropic than geotropic.

Answer 5

Aim:

To prove that roots are more positively hydrotropic than geotropic.

Apparatus:

Wire netting or gauze, wires, moist sawdust, germinating bean seeds

Procedure:

Take a piece of wire netting or gauze and suspend it with the help of wires.

Place moist sawdust of about 1 inch on the wire netting.

Embed some germinating bean seeds in the sawdust.

Observation:

Inference:

D. STRUCTURED / APPLICATION / SKILL TYPE

Chapter-7,Chemical Coordination in plant

Question 1

(a) Name the scientific phenomenon that is being overcome by pruning.

(b) What plant hormone is responsible for the scientific phenomenon mentioned in (a).

Answer 1

(a) Apical dominance

(b) Auxins

Question 2

The figure given below shows the stages of ripening in a banana. Answer the questions that follow:

(a) Name the plant hormone responsible for the above changes.

(b) Mention two characteristic features of this hormone.

Answer 2

(a) Ethylene

(b) Characteristic features of ethylene:

Site of synthesis:

o It is synthesised in senescent leaves and flowers, germinating seeds and ripening fruits.

Functions:

o Induces and promotes fruit ripening

o Promotes fruit ripening

Acids Bases and Salts Selina Solution Chapter 3 Intext 1

Question 1

(a) What do you understand by the term, acid?

(b) Name the positive ion formed when an acid is dissolved in water.

Answer 1

(a) Acids are defined as compounds which contain one or more hydrogen atoms, and when dissolved in water, they produce hydronium ions (H₃O⁺), the only positively charged ions.

(b) Hydronium ion

Question 2

Write the ionisation reaction of sulphuric acid showing the formation of hydronium ion.

Answer 2

H2SO4 + H₂O ⇌ H₃O⁺ + HSO4-

HSO4- + H₂O ⇌ H₃O⁺ + SO4-2

Question 3 :

Water is never added to acid in order to dilute it. Why?

Answer 3 :

If water is added to a concentrated acid, the heat generated causes the mixture to splash out and cause severe burns. Thus, water is never added to acid in order to dilute it.

Question 4 :

Define the term ‘basicity’ of an acid. Give the basicity of: nitric acid, sulphuric acid, phosphoric acid?

Answer 4 :

Basicity: The basicity of an acid is defined as the number of hydronium ions (H₃O⁺) that can be produced by the ionization of one molecule of that acid in aqueous solution.

The basicity of following compounds are:

Nitric acid:Basicity= 1

Sulphuric acid: Basicity=2

Phosphoric acid: Basicity=3

Question 5 :

Give two examples of each of the following:

(a) Oxy-acid

(b) Hydracid

(d) Dibasic acid

Answer 5

(a) Oxyacids: – HNO₃, H₂SO₄

(b) Hydracid:- HCl, HBr

(d) Dibasic acid: – H₂SO₄ , H₂CO₃

Question 6

Name the

(a) acidic anhydride of the following acids:

(i) Sulphurous acid

(ii) Nitric acid

(iii) Phosphoric acid

(iv) Carbonic acid

(b) Acids present in vinegar, grapes and lemon?

Answer 6

(a) The anhydride of following acids are:

(i) Sulphurous acid: SO₂

(ii) Nitric acid: N₂O₅

(iii) Phosphoric acid: P₂O₅

(iv) Carbonic acid: CO₂

(b) Acids present in following are:

Vinegar: Acetic acid

Grapes: Tartaric acid and Malic acid

Lemon: Citric acid

Question 7

What do you understand by the statement ‘acetic acid is a mono basic’ acid?

Answer 7

Acetic acid is a mono basic acid which on ionization in water produce one hydronium ion per molecule of the acid.

Question 8

Give a balanced equation for (i) reaction of nitrogen dioxide with water (ii) Preparation of non-volatile acid from a volatile acid.

Answer 8

(i) 2NO_2(g) + H₂O_(l)→ HNO_2(aq) + HNO₃

(ii) H₂S₂O₇ + H₂O → 2 H₂SO₄

Question 9

What do you understand by the strength of acid? On which factors does the strength of an acid depend?

Answer 9

The strength of an acid is the extent to which the acid ionizes or dissociates in water.

The strength of an acid depends on the degree of ionization and concentration of hydronium ions [H₃O⁺] produced by that acid in aqueous solution.

Question 10

Explain the following:

(a)Carbonic acid gives an acid salt but hydrochloric acid does not. Explain.

(b) Dil. HCl acid is stronger than highly concentrated acetic acid. Explain.

(d) Lead carbonate does not react with dilute HCl.

(e) Nitrogen dioxide is a double acid anhydride.

Answer 10

(a)

Carbonic acid is a dibasic acid with two replaceable hydrogen ions; therefore it forms one acid salt or one normal salt.

Hydrochloric acid is a monobasic acid with one replaceable hydrogen ion and so forms only one normal salt.

(b)

Strength of an acid is the measure of concentration of hydronium ions it produces in its aqueous solution. Dil. HCl produces high concentration of hydronium ion compared to that of concentrated acetic acid. Thus, dil. HCl is stronger acid than highly concentrated acetic acid.

(c)

H₃PO₃ is not a tribasic acid because in oxyacids of phosphorus, hydrogen atoms which are attached to oxygen atoms are replaceable. Hydrogen atoms directly bonded to phosphorus atoms are not replaceable.

(d)

The salt produced is insoluble in the solution so the reaction does not proceed. Hence, we do not expect lead carbonate to react with hydrochloric acid.

(e)

NO₂ is called double acid anhydride because two acids – nitrous acid and nitric acid – are formed when it reacts with water.

2NO₂ + H₂O → HNO₂ + HNO₃

Question 11

How is an acid prepared from a (a) non-metal (b) salt? Give an equation for each.

Answer 11

(a) Acids are prepared from non-metals by their oxidation. For example :

Sulphur or phosphorus is oxidized by conc. Nitric acid to form sulphuric acid or phosphoric acid.

(b) Acids are prepared from salt by the displacement reaction. For example :

Nitric acid is prepared by using H₂SO₄and sodium chloride.

Question 12

Give an equation to show how the following are made from their corresponding anhydrides.

(a) Sulphurous acid

(b) Phosphoric acid

(d) Sulphuric acid

Answer 12

(a) SO₂ +H₂O-à H₂SO₃

(b) P₂O₅ +3H₂O-à 2H₃PO₄

(d)SO₃ + H₂O---àH₂SO₄

Question 13

Name an acid used:

(a) To flavor and preserve food

(b) In a drink

(d) As an eyewash

Answer 13

(a) Citric acid

(b) Carbonic acid

(d) Boric acid

Question 14

Give the reaction of acids with

(a) Chlorides

(b) Nitrates

State the conditions under which they react.

Answer 14

(a) Chlorides react with concentrated sulphuric acid on warming to liberate hydrogen chloride.

(b) Nitrates when heated with conc. sulphuric acid produce more volatile nitric acid.

Both chlorides and nitrates do not react with dilute acids; they react with concentrated acids.

Acids Bases and Salts 10 Exe-3 A

Question 1

What do you understand by an alkali? Give two examples of :

(a) Strong alkalis

(b) Weak alkalis

Answer 1

An alkali is a basic hydroxide which when dissolved in water produces hydroxyl ions (OH^–) as the only negatively charged ions.

(a) Strong alkalis: Sodium hydroxide , Potassium hydroxide

(b) Weak alkalis: Calcium hydroxide , Ammonium hydroxide

Question 2

What is the difference between :

(a) An alkali and a base

(b) The chemical nature of an aqueous solution of HCl and an aqueous solution of NH₃

Answer 2

(a) An alkali and a base:

(i) Alkalis are soluble in water whereas bases may be or may not be soluble in water.

(ii) All alkalis are bases but all bases are not alkalis.

(b) The chemical nature of an aqueous solution of HCl and an aqueous solution of NH₃

(i) The aqueoussolution of HCl is acidic in nature. It can turn blue litmus to red.

(ii) The aqueoussolution of NH₃is basic in nature. It can turn red litmus to blue.

Question 3

Name the ions furnished by

(a) bases in solution

(b) an acid

Answer 3

(a) Hydroxyl ion (OH^–)

(b) H⁺

Question 4

Give one example in each case:

(a) A basic oxide which is soluble in water,

(b) A hydroxide which is highly soluble in water,

(d) A hydroxide which is insoluble in water,

(e) A weak mineral acid,

(f) A base which is not an alkali,

(g) An oxide which is a base,

(h) A hydrogen containing compound which is not an acid,

(i) A base which does not contain a metal ion.

Answer 4

(a) Barium oxide

(b) Sodium hydroxide

(d) Cupper hydroxide

(e) Carbonic acid

(f) Ferric hydroxide

(g) Copper oxide

(h) Ammonia

(i) Ammonium hydroxide

Question 5

You have been provided with three test tubes. One of them contains distilled water and the other two have an acidic solution and a basic solution respectively. If you are given red litmus paper, how will you identify the contents of each test tube?

Answer 5

The test tube containing distilled water does not affect the red litmus paper.

The test tube containing acidic solution does not change the red litmus paper.

But the test tube containing basic solution turns red litmus paper blue.

Question 6

HCl, HNO₃, C₂H₅OH, C₆H₁₂O₆ all contain H atoms but only HCl and HNO₃ show acidic character. Why?

Answer 6

It is because HCl and HNO₃ ionize in aqueous solution whereas ethanol and glucose do not ionize in aqueous solution.

Question 7

(a) DryHCl gas does not change the colour of dry litmus paper. Why?

(b) lsPbO₂ a base or not? Comment.

Answer 7

(a) DryHCl gas does not contain any hydrogen ions in it, so it does not show acidic behaviour. Hence, dry HCl gas does not change the colour of dry litmus paper.

(b) Lead oxide is a metallic oxide which reacts with hydrochloric acid to produce lead chloride and water, but it is excluded from the class of bases, because chlorine is also produced.

PbO₂ + 4HCl → PbCl₂ + Cl₂ + 2H₂O

Thus, lead oxide is not a base.

(c) Yes, basic solutions have H⁺ions, but the concentration of OH^– ions is more than the H⁺ ions which makes the solution basic in nature.

Question 8

How would you obtain:

(a) A base from other base

(b) An alkali from a base

Answer 8

(a) We can obtain a base from another base by double decomposition. The aqueous solution of salts with base precipitates the respective metallic hydroxide.

FeCl₃ +3NaOH Fe(OH)₃ +3NaCl

(b) An alkali from a base

_(c) Salt from another salt

Question 9

Write balanced equations to satisfy each statement.

(a) Acid + Active metal Salt + Hydrogen

(b) Acid + base Salt + Water

(d) Acid + sulphite or bisulphit e salt + water + sulphur dioxide

(e) Acid + Sulphide Salt + hydrogen sulphide

Answer 9

(a) Mg +2HCl --àMgCl₂ + H₂

(b) HCl + NaOH---à NaCl + H₂O

(d) CaSO₃ + 2HCl----à CaCl₂ + H₂O+ SO₂

(e) ZnS + 2HCl--à ZnCl₂ + H₂S

Question 10

The skin has and needs natural oils. Why is it advisable to wear gloves while working with strong alkalis?

Answer 10

As we know that alkalis react with oil to form soap. As our skin contains oil so when we touch strong alkalis, a reaction takes place and soapy solution is formed. Hence we should wear gloves.

Answer 11 (complete the table)

Indicator

Neutral

Acidic

Alkaline

Litmus

Phenol-phthalein

Purple

Colourless

Blue to red

Colourless

Red to blue

Pink

Question 12

What do you understand by pH value? Two solutions X and Y have pH values of 4 and 10, respectively. Which one of these two will give a pink colour with phenolphthalein indicator?

Answer 12

pH represents the strength of acids and alkalis expressed in terms of hydrogen ion concentration.

The solution with pH value 10 will give pink colour with phenolphthalein indicator.

Question 13

You are supplied with five solutions : A , B , C , D and E with pH values as follows:

A =1.8 , B=7 , C=8.5 , D=13 and E=5

Classify these solutions as neutral, slightly or strongly acidic and slightly or strongly alkaline.

Which solution would be most likely to liberate hydrogen with:

(a) Magnesium powder

(b) Powered zinc metal. Give a word equation for each reaction.

Answer 13

A = Strongly acidic

B= neutral

C=Weakly alkaline

D= Strongly alkaline

E= Weakly acidic

(a) Solution A (acidic solution) + Mg-àH₂ + Mg salt

(b) SolutionA (acidic solution) + Zn-àH₂ + Zn salt

Question 14

Distinguish between :

(a) A common acid-base indicator and a universal indicator

(b) The acidity of bases and basicity of acids

Answer 14

(a) A common acid-base indicator and a universal indicator:

An acid-base indicator like litmus tells us only whether a given substance is an acid or a base. The universal indicator gives an idea as to how acidic or basic a substance is universal indicator gives different colours with solutions of different pH values.

(b) The acidity of bases and basicity of acids

The acidity of bases: The number of hydroxyl ions which can be produced per molecule of the base in aqueous solution.

Basicity of acid: The basicity of an acid is defined as the number of hydronium ions that can be produced by the ionization of one molecule of that acid in aqueous solution.

An acid is that substance which gives H⁺ ions when dissolved in water.

An alkali is that substance which gives OH^– ions when dissolved in water.

Question 15

What should be added to

(a) Increase the pH value

(b) Decrease the pH value of a neutral solution?

Answer 15

(a) Alkali

(b) Acid

Question 16

How does tooth enamel get damaged? What should be done to prevent it?

Answer 16

Substances like chocolates and sweets are degraded by bacteria present in our mouth. When the pH falls to 5.5 tooth decay starts. Tooth enamel is the hardest substance in our body and it gets corroded. The saliva produced by salivary glands is slightly alkaline, it helps to increase the pH, to some extent, but toothpaste which contains basic substance is used to neutralize excess acid in the mouth.

Question 17

When you use universal indicator, you see that solutions of different acids produce different colours. Indeed, solution of the same acid with different concentrations will also give different colours. Why?

Answer 17

A universal indicator is a mixture of dyes which identify a gradual change of various colours over a wide range of pH, depending on the strength of the acid. When we use a universal indicator, we see solutions of different acids produce different colours. Indeed, solutions of the same acid with different concentration give different colours.

The more acidic solutions turn universal indicator bright red. A less acidic solution will only turn it orange-yellow. Colour differences can also be observed in case of vinegar which is less acidic and battery acid which is more acidic.

Question 18

(a) A solution has a pH of 7. Explain how you would

(i) increase its pH

(ii) decrease its pH

(b) If a solution changes thecolour of litmus from red to blue, what can you say about its pH?

Answer 18

(a)

(i) The pH can be increased by adding a basic solution.

(ii) The pH can be increased by adding an acidic solution.

(b) The solution is basic in nature and the pH value will be more than 7.

Question 19

Solution P has a pH of 13, solution Q has a pH of 6 and solution R has a pH of 2.

Which solution

(a) will liberate ammonia from ammonium sulphate on heating?

(b) is a strong acid?

Answer 19

(a) Solution P

(b) Solution R

Excercise – 3(B)

Question 1

Define the following and give two examples in each case:

(a) a normal salt, (b) an acid salt, (c) a mixed salt.

Answer 1

(a) A normal salt:

Normal salts are the salts formed by the complete replacement of the ionizable hydrogen atoms of an acid by a metallic or an ammonium ion.

(b) An acidic salt:

Acid salts are formed by the partial replacement of the ionizable hydrogen atoms of a polybasic acid by a metal or an ammonium ion.

Mixed salts are those salts that contain more than one basic or acid radical.

Examples:

(a) A Normal salt: Na₂SO₄ , NaCl

(b) An acid salt: NaHSO₄ , Na₂HPO₄

Question 2

Answer the following questions related to salts and their preparations:

(a) What is a salt?

(b) What kind of salt is prepared by precipitation?

(c) Name a salt prepared by the direct combination. Write an equation for the reaction that takes place in preparing the salt you have named.

(d) Name the procedure used to prepare a sodium salt such as sodium sulphate.

Answer 2

(a) Salt is a compound formed by the partial or total replacement of the ionizable hydrogen atoms of an acid by a metallic ion or an ammonium ion.

(b) An insoluble salt can be prepared by precipitation.

Reaction:

2Fe +3Cl₂ 2FeCl₃

(d) By neutralizing sodium carbonate or sodium hydroxide with dilute sulphuric acid:

Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂

2 NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

Question 3

Describe giving all practical details , how would you prepare :

(a) Copper sulphate crystals from mixture of charcoal and black copper oxide,

(b) Zinc sulphate crystals from Zinc dust (powered Zinc and Zinc oxide)

(d) Calcium sulphate from calcium carbonate

Answer 3

(a) Copper sulphate crystals from a mixture of charcoal and black copper oxide:

The carbon in the charcoal reduces the black copper oxide to reddish-brown copper. The lid must not be removed until the crucible is cool or the hot copper will be re-oxidized by air.

Take dilute sulphuric acid in a beaker and heat it on wire gauze. Add cupric oxide in small quantities at a time, with stirring till no more of it dissolves and the excess compound settles to the bottom.

Filter it hot and collect the filtrate in a china dish. Evaporate the filtrate by heating to the point of crystallization and then allow it to cool and collect the crystals of copper sulphate pentahydrate.

Reaction: CuO + H₂SO₄--à CuSO₄ + H₂O

CuSO₄ + 5H₂O--à CuSO_4. 5H₂O

(b) Zinc sulphate crystals from Zinc dust:

Take dilute sulphuric acid in a beaker and heat it on wire gauze. Add some granulated zinc pieces with constant stirring. Add till the Zinc settles at the base of the beaker. Effervescences take place because of the liberation of hydrogen gas. When effervescence stops, it indicates that all the acid has been used up. The excess of zinc is filtered off. Collect the solution in a china dish and evaporate the solution to get crystals. Filter, wash them with water and dry them between the folds of paper. The white needle crystals are of hydrated Zinc sulphate.

Reaction:Zn + H₂SO₄---à ZnSO₄ + H₂

ZnSO₄ +7 H₂O-----à ZnSO_4. 7 H₂O

Metallic lead is converted to lead oxide by oxidation. Then lead sulphate is prepared from insoluble lead oxide, by first converting it into soluble lead nitrate. Then the lead nitrate solution is treated with sulphuric acid to obtain white ppt. of Lead sulphate.

Reaction:

PbO +2HNO₃---à Pb(NO₃)₂ + H₂O

Pb(NO₃)₂ + H₂SO₄----à PbSO₄ + 2HNO₃

(d)Sodium hydrogen carbonate crystals:

Dissolve 5 grams of anhydrous sodium carbonate in about 25 ml of distilled water in a flask. Cool the solution by keeping the flask in a freezing mixture. Pass carbon dioxide gas in the solution. Crystals of sodium bicarbonate will precipitate out after some time. Filter the crystals and dry it in folds of filter paper.

Reaction: Na₂CO₃ + CO₂ + H₂O----à 2NaHCO₃

Question 4

The following is the list of methods for the preparation of salts.

A-Direct combination of two elements.

B-reaction of dilute acid with a metal.

C-reaction of dilute acid with an insoluble base.

D-Titration of dilute acid with a solution of soluble base.

E- reaction of two solutions of salts to form a precipitate.

Choose from the above list A to E , the best method of preparing the following salts by giving a suitable equation in each case:

1. Anhydrous ferric chloride,

2. Lead chloride,

3. Sodiumsulphate,

4. Coppersulphate.

Answer 4

1. Anhydrous ferric chloride: -A (Direct combination of two elements)

2Fe + 3Cl₂ 2FeCl₃

2.Lead chloride: -E (Reaction of two solutions of salts to form a precipitate)

Pb(NO₃)₂ +2HCl PbCl₂ +2HNO₃

3.Sodium sulphate: – D( Titration of dilute acid with a solution of soluble base)

2NaOH + H₂SO₄ Na₂SO₄+2H₂O

4. Coppersulphate:- C (reaction of dilute acid with an insoluble base)

Cu(OH)₂ +H₂SO₄ CuSO₄ + 2H₂O

Question 5

Name:

(a) A chloride which is insoluble in cold water but dissolves in hot water,

(b) A chloride which is insoluble,

(d) A basic salt,

(e) An acidic salt,

(f) A mixed salt,

(g) A complex salt,

(h) A double salt,

(i) a salts whose solubility increases with temperature,

(j) A salt whose solubility decreases with temperature.

Answer 5

(a) Lead chloride

(b) Silver chloride

(d) Basic lead chloride

(e) Sodium hydrogen sulphate

(f) Sodium potassium carbonate

(g) Sodium argentocyanide

(h) Potash alum

(i) Potassium bromide and potassium chloride

(j) Calcium sulphate

Question 6

Fill in the blanks with suitable words:

An acid is a compound which when dissolved in water forms hydronium ions as the only …………… ions. A base is a compound which is soluble in water and contains …………….. ions. A base reacts with an acid to form a …………….. and water only. This type of reaction is known as …………….

Answer 6

An acid is a compound which when dissolved in water forms hydronium ions as the only positively charged ions. A base is a compound which is soluble in water and contains hydroxide ions. A base reacts with an acid to form a salt and water only. This type of reaction is known as neutralisation.

Question 7

What would you observe when:

(a) Blue litmus is introduced into a solution of hydrogen choride gas.

(b) Red litmus paper is introduced into a solution of ammonia in water

Answer 7

(a) Blue litmus will turn into red which will indicate the solution to be acidic.

(b) No change will be observed.

Question 8

Explain why:

(a) It is necessary to find out the ratio of reactants required in the preparation of sodium sulphate.

(b) Fused calcium chloride is used in the preparation of FeCl₃.

Answer 8

(a) Since sodium hydroxide and sulphuric acid are both soluble, an excess of either of them cannot be removed by filtration. Therefore it is necessary to find out on small scale, the ratio of solutions of the two reactants.

(b) As iron chloride is highly deliquescent, so it is kept dry with the help of fused calcium chloride.

(c) On heating the hydrate, HCl acid is released and basic salt (FeOCl) or ferric oxide remains. Hence, anhydrous ferric chloride cannot be prepared by heating the hydrate.

Question 9

Give the preparation of the salt shown in the left column by matching with the methods given in the right column. Write a balanced equation for each preparation.

Salt Method of preparation

Zinc Sulphate Precipitation

Ferrous sulphide Oxidation

Barium Sulphate Displacement

Ferric sulphate Neutralisation

Sodium sulphate Synthesis

Answer 9

Zinc Sulphate – Displacement

Ferrous sulphide – synthesis

Barium sulphate – Precipitation

Ferric Sulphate- Oxidation

Sodium sulphate – Neutralisation

Question 10

(a) Give the pH value of pure water. Does it change if common salt is added to it?

(b) Classify the following solutions as acids, bases or salts. Ammonium hydroxide, barium chloride, sodium chloride, sodium hydroxide, H₂SO₄ and HNO₃

Answer 10

(a) pH of pure water is 7 at 25^oC. No, the pH does not change when common salt is added.

(b) Acids: H₂SO₄ and HNO₃

Bases: Ammonium hydroxide and sodium hydroxide.

Salts: Barium chloride and sodium chloride.

Question 11

Define the term neutralization.

(a) Give a reaction, mentioning clearly acid and base used in the reaction.

(b) If one mole of a strong acid reacts with one mole of a strong base, the heat produced is always same. Why?

Answer 11

Neutralization is the process by which H⁺ ions of an acid react completely with the [OH]^– ions of a base to give salt and water only.

(a)

(b) Neutralization is simply a reaction between H⁺ ions given by strong acid and OH^– ions given by strong base. In case of all strong acids and strong bases, the number of H⁺ and OH^– ions produced by one mole of a strong acid or strong base is always same. Hence the heat of neutralization of a strong acid with strong base is always same.

Question 12

Write the balanced equation for the preparation of the following salts in the laboratory:

(a) A soluble sulphate by the action of an acid on an insoluble base,

(b) An insoluble salt by the action of an acid on another salt,

(d) A soluble sulphate by the action of an acid on a metal.

Answer 12

_(a) CuO+ H₂SO₄---àCuSO₄ +H₂O

_(b)

(c)

_(d)

Question 13

You are provided with the following chemicals:

NaOH,Na₂CO₃,H₂O,Zn(OH)₂,CO₂,HCl,Fe,H₂SO₄,Cl₂,Zn

Using suitable chemicals from the given list only, state briefly how you would prepare:

(a) Iron(III) chloride,

(b) Sodium sulphate,

(d) Iron(II) sulphate,

(e) Sodium chloride.

Answer 13

(a) Iron (III) Chloride: Iron chloride is formed by direct combination of elements.

_(b) Sodium sulphate: By neutralization of caustic soda with dilute sulphuric acid

_(c) Sodium zincate: By the action of metals with alkalis

_(d) Iron (II) sulphate: Iron sulphate is prepared by the action of dilute acid on an active metal.

_(e) Sodium chloride: By the neutralization reaction of strong acid with strong base

Question 14

For each of the salt: A, B, C and D, suggest a suitable method of its preparation.

(a) A is a sodium salt.

(b) B is an insoluble salt.

(d) D is a soluble salt of zinc.

Answer 14

(a) By neutralisation:

NaOH + HCl → NaCl + H₂O

(b) By precipitation:

Pb(NO₃)₂ + 2NaCl → PbCl₂ + 2NaNO₃

(d) Simple displacement:

Zn + H₂SO₄→ ZnSO₄ + H₂

Question 15

Choosing only substances from the list given in the box below, write equations for the reactions which you would use in the laboratory to obtain:

(a) Sodium sulphate

(b) Copper sulphate

(d) Zinc carbonate

Answer 15

(a) Na2CO3+ H2SO4 (dil) → Na2SO4 + H2O + CO2

(b) CuCO3+ H2SO4 (dil) → CuSO4 + H2O + CO2

(d) Zn + H2SO4(dil) → ZnSO4 + H2

(e) ZnSO4 + Na2CO3 → ZnCO3 + Na2SO4

Question 16

From the formula listed below, choose one, in each case, corresponding to the salt having the given description: AgCl, CuCO₃, CuSO₄.5H₂O, KNO₃, NaCl, NaHSO₄, Pb(NO₃)₂, ZnCO₃, ZnSO₄.7H₂O.

(a) an acid salt

(b) an insoluble chloride

(d) on heating, this salt changes from green to black

(e) this salt gives nitrogen dioxide on heating

Answer 16

(a) NaHSO₄

(b) AgCl

(d) CuCO₃

(d) Pb(NO₃)₂

Question 17

(a) Ca(H₂PO₄)₂is an example of a compound called _______ (acid salt/basic salt/normal salt).

(b) Write the balanced equation for the reaction of: A named acid and a named alkali.

Answer 17

(a) acid salt

(b) NaOH+ HCl → NaCl + H₂O

Question 18

State the terms defined by the following sentences:

(a) A soluble base.

(b) The insoluble solid formed when two solutions are mixed together.

Solution 18

(a) Alkali

(b) Precipitate

Question 19

Which of the following methods, A, B, C, D or E is generally used for preparing the chlorides listed below from (i) to (v). Answer by writing down the chloride and the letter pertaining to the corresponding method. Each letter is to be used only once.

A Action of an acid on a metal

B Action of an acid on an oxide or carbonate

C Direct combination

D Neutralisation of an alkali by an acid

E Precipitation (double decomposition)

(i) Copper (II) chloride

(ii) Iron (II) chloride

(iii). Iron (III) chloride

(iv) Lead (II) chloride

(v) Sodium chloride

Answer 19

(i) Copper (II) chloride – B

(ii) Iron (II) chloride – A

(iii). Iron (III) chloride – C

(iv) Lead (II) chloride – E

(v) Sodium chloride – D

Answer 20

Reactants	Products	Method
Soluble base + Acid (dil)	Salt + water	Neutralisation Titration
Metal + Non-metal	Salt (soluble/insoluble)	Direct Combination
Insoluble base +	Salt (soluble) + water	…………….
Active metal + Acid (dil)	Salt + Hydrogen	Displacement
Soluble salt solution (A) + Soluble salt solution (B)	Precipitated salt + Soluble salt	Precipitation
Carbonate /bicarbonate + Acid (dil)	Salt + Water+ Carbon dioxide	Decomposition of carbonate
Chlorides/nitrates + Acid (conc)	Acid salt + HCl/HNO₃	Decomposition of chlorides and nitrates

Exercise – 3(C)

Question 1

Salts are prepared by the following methods:

(a) Direct combination

(b) Displacement

(d) Neutralisation of insoluble base

(e) Neutralisation of an alkali (titration)

Answer 1

(a) Direct combination: Iron(III) chloride

(b) Displacement: ZnSO₄

(d) Neutralisation of insoluble base: MgCl₂

(e) Neutralisation of an alkali (titration): NaCl

Question 2

M is an element in the form of a powder. M burns in oxygen and the product obtained is soluble in water. The solution is tested with litmus. Write down only the word which will correctly complete each of the following sentences.

(i) If M is a metal, then the litmus will turn _____.

(ii) If M is a non-metal, then the litmus will turn _____.

(iii) If M is a reactive metal, then _____ will be evolved when M reacts with dilute sulphuric acid.

(iv) If M is a metal, it will form _____ oxide, which will form ______ solution with water.

(v) If M is a non-metal, it will not conduct electricity in the form of ______.

Answer 2

(i) blue

(ii) red

(iii) hydrogen gas

(iv) basic, alkaline

(v)graphite

Question 3 :

What do you understand by water of crystallisation?

Give four substances which contain water of crystallisation and write their common names.

Answer 3 :

It is the amount of water molecules which enter into loose chemical combination with one molecule of the substance on crystallization from its aqueous solution.

Common name	Chemical name	Formula
Washing soda	Sodium carbonate dehydrate	Na₂CO₃.10H₂O
Epsom salt	Magnesium sulphate heptahydrate	MgSO₄. 7H₂O
Potash alum	Hydrated potassiumaluminium sulphate	K₂SO₄.Al(SO₄)₃.24H₂O
Gypsum	Hydrated calcium sulphate	CaSO₄.2H₂O

Question 4

(a) Define efflorescence. Give examples.

(b) Define deliquescence. Give examples.

Answer 4

(a) Crystalline hydrated salts which on exposure to the atmosphere lose their water of crystallisation partly or completely and change into a powder. This phenomenon is called efflorescent and the salts are called efflorescent.

Examples: CuSO₄.5H₂O, MgSO₄.7H₂O, Na₂CO₃.10H₂O

(b) Water-soluble salts which on exposure to the atmosphere absorb moisture from the atmosphere and dissolve in the same and change into a solution. The phenomenon is called deliquescence and the salts are called deliquescent.

Examples: CaCl₂, MgCl₂, ZnCl₂

Question 5

Distinguish between drying and dehydrating agent.

Answer 5

Drying agents	Dehydrating agents
remove moisture from other substances.	remove chemically combined elements of water in the ratio of 2:1 (hydrogen:oxygen) from a compound.
They are used to dry gases like chlorine, sulphur dioxide and hydrogen chloride. are also used in dessicators to keep substances dry.	prepare substances such as carbon monoxide and sugar charcoal.
represent a physical change.	represent a chemical change.

Question 6

Explain clearly how conc. H₂SO₄ is used as a dehydrating as well as a drying agent.

Answer 6

Conc. sulphuric acid is hygroscopic in nature and can remove moisture from other substances; therefore, it is used as a drying agent.

It is also used as a dehydrating agent because it has a strong affinity for water and thus absorbs water quickly from compounds.

Question 7

Give reasons for the following:

(a) Sodium hydrogen sulphate is not an acid, but it dissolves in water to give hydrogen ions according to the equation

NaHSO₄⇌ H⁺ + Na⁺ + SO₄^2-

(b) Anhydrous calcium chloride is used in adesiccator.

Answer 7

(a) Sodium hydrogen sulphate [NaHSO₄] is an acid salt and is formed by the partial replacement of the replaceable hydrogen ion in a dibasic acid [H₂SO₄]. The [H] atom in NaHSO₄ makes it behave like an acid.

So, on dissolving in water, it gives hydrogen ions.

(b) Desiccating agentsare used to absorb moisture. Anhydrous calcium chloride (CaCl₂) has the capacity of absorbing moisture as it is hygroscopic in nature. So, it is used in a desiccator.

Question 8

State whether a sample of each of the following would increase or decrease in mass if exposed to air.

(a) Solid NaOH

(b) Solid CaCl₂

(d) Conc. sulphuric acid

(e) Iron (III) chloride

Answer 8

(a) Increase

(b) Increase

(d) Increase

(e) Increase

Question 9

(a) Why does common salt get wet during the rainy season?

(b) How can this impurity be removed?

(d) Name two crystalline substances which do not contain water of crystallisation.

Answer 9

(a) Table salt turns moist and ultimately forms a solution on exposure to air especially during the rainy season. Although pure sodium chloride is not deliquescent, the commercial version of the salt contains impurities (such as magnesium chloride) which are deliquescent substances.

(b) The impurity can be removed by passing a current of dry hydrogen chloride gas through a saturated solution of the affected salt. Pure sodium chloride is produced as a precipitate which can be recovered by filtering and washing first with a little water and finally with alcohol.

(d) Common salt and sugar

Question 10

Name the salt which on hydrolysis forms

(a) Acidic

(b) Basic acid

Answer 10

(a) Iron chloride(FeCl₃)

FeCl₃ + 3H₂O → 3HCl + Fe(OH)₃

(b) Ammonium acetate (CH₃COONH₄)

CH₃COONH₄+H₂O → CH₃COOH + NH₄OH

NaCl_(s) + H₂O → Na⁺_(aq) OH^–_(aq) + H₂O

Question 11

State the change noticed when blue litmus and red litmus are introduced in the following solutions:

(a) Na₂CO₃ solution

(b) NaCl solution

(d) MgCl₂ Solution

Answer 11

(a) Na₂CO₃ solution: This solution is alkaline in nature; hence, red litmus changes to blue.

(b) NaCl solution: There is no change in the colour of the litmus paper because this solution is neutral.

(d) MgCl₂: It is slightly acidic and neutral; hence, there is no change in the litmus paper.

Question 12

Answer the questions below relating your answers only to salts in the following list: Sodium chloride, anhydrous calcium chloride, copper sulphate-5-water?

(a) What name is given to the water in the compound copper sulphate-5-water?

(b) If copper sulphate-5-water is heated, anhydrous copper sulphate is formed. What is its colour?

(d) Which one of the salts in the given list is deliquescent?

Answer 12

(a) Water of crystallization

(b) White

(d) Anhydrous calcium chloride

Question 13

State your observation when

(a) Washing soda crystals

(b) Iron (III) chloride salts are exposed to the atmosphere.

Answer 13

(a) When washing soda (Na₂CO₃.10H₂O) is exposed to air, it loses 9 molecules of water to form a monohydrate.

(b) It absorbs moisture from the atmosphere and becomes moist and ultimately dissolves in the absorbed water, forming a saturated solution.

Selina Solution Acids Bases and Salts Chapter 3

Excercise – Misc

Question 1 :

Write the balanced equations for the preparation of the following compounds (as major product) starting from iron and using only one other substance:

(a) Iron (II) chloride

(b) Iron (III) chloride

(d) Iron (II) sulphide

Answer 1

(a) Fe + 2HCl (dil) FeCl₂ + H₂

(bi) 2Fe (heated) + 3Cl₂ (dry) 2FeCl₃

(d) Fe + S FeS

Question 2

Write a balanced reaction for the following conversions (A, B, C, D)

A: Fe + 2HCl → FeCl₂ + H₂

B: FeCl₂ + Zn→ ZnCl₂ + Fe

Fe + H₂CO₃→ FeCO₃ + H₂↑

C: FeCO₃ + 2HNO₃→ Fe (NO₃)₂ + H₂O + CO₂

D: Fe(NO₃)₂ + 2NaOH → Fe(OH)₂ + 2NaNO₃

Question 3

The preparation of Lead sulphate from Lead carbonate is a two-step process. (Lead sulphate cannot be prepared by adding dilute Sulphuric acid to Lead carbonate.)

(a) What is the first step that is required to prepare Lead sulphate from Lead carbonate?

(b) Write the equation for the reaction that will take place when this first step is carried out.

(c) Why is the direct addition of dilute sulphuric acid to Lead carbonate an impractical method of preparing Lead sulphate?

Answer 3

(a) The first step is to convert insoluble lead carbonate into soluble lead nitrate by treating lead carbonate with dilute nitric acid.

(b) PbCO₃ (s) + 2HNO₃(dil)-----àP b(NO₃)₂ (aq) + H₂O (l) + CO₂

(c) When dilute sulphuric acid is added directly to lead carbonate, the lead sulphate thus formed will be deposited on solid lead carbonate disconnecting lead carbonate from sulphuric acid.

Question 4

(a) What are the terms defined by the following?

(i) A salt containing a metal ion surrounded by other ions or molecules.

(ii) A base which is soluble in water.

(b) Making use only of substances chosen from those given below:

Dilute sulphuric acid, Sodium Carbonate

Zinc, Sodium sulphite

Lead, Calcium carbonate

Give equations for the reactions by which you could obtain :

(i) Hydrogen

(ii) Sulphur dioxide

(iii) Carbon dioxide

(iv) Zinc carbonate (two steps required)

Answer 4

(i) Complex salts

(ii) Alkali

b)(i) Zn+H₂SO₄-----àZnSO₄+ H₂

(ii) Na₂SO₃+ H₂SO₄-----àNa₂SO₄ + H₂O +SO₂

(iii) ) CaCO₃+ H₂SO₄-----àCaSO₄ + H₂O +CO₂

(iv) first step: Zn+H₂SO₄-----àZnSO₄+ H₂

Second step: ZnSO_4(sol) + Na₂CO_3(sol)-----à ZnCO₃+Na₂SO₄

CLASS 10 BIOLOGY

Circulatory System Chapter-8

Question 1

Agranulocytes are:

(a) lymphocytes and monocytes

(b) lymphocytes and basophils

(d) eosinophils and monocytes

Answer 1

(a) lymphocytes and monocytes

Question 2

White blood cells engulf bacteria in a process called:

(a) diapedesis

(b) phagocytosis

(d) passive transport

Answer 2

(b) phagocytosis

Question 3

The nearest organ to which the heart supplies oxygenated blood is

(a) Lung

(b) Stomach

(d) Heart itself

Answer 3

(d) Heart itself

Question 4

When a doctor is recording your pulse, he is pressing on your wrist exactly on a

(a) vein

(b) capillary

(d) arteriole

Answer 4

Question 5

The blood vessels supplying blood to the kidney is the

(a) renal vein

(b) renal artery

(d) hepatic vein

Answer 5

(b) renal artery

Question 6

Angina Pectoris is due to

(a) defective nutrition

(b) chest pain due to inadequate supply of oxygen to the heart muscle

(d) infection by a virus

Answer 6

(b) chest pain due to inadequate supply of oxygen to the heart muscle

Question 7

The chief function of lymph nodes is to

(a) produce WBCs

(b) produce hormones

(d) destroy pathogens

Answer 7

(d) destroy pathogens

Question 8

Heart sounds are produced due to

(a) closure of tricuspid and bicuspid valves

(b) rushing of blood through valves producing turbulence

(d) entry of blood into auricles

Answer 8

(a) closure of tricuspid and bicuspid valves

(b) rushing of blood through valves producing turbulence

B.VERY SHORT ANSWER TYPE

Chapter – 8, Circulatory System ICSE Class-10

Question 1

Given below are certain structures, write their chief functional activity.

(a) Blood platelets ——

(b) Neutrophils —–

(d) Lymphocytes —–

(e) Bone marrow —–

Answer 1

(a) Blood platelets and blood coagulation

(b) Neutrophils and phagocytosis

(d) Lymphocytes and Produce antibodies

(e) Bone marrow and destruction of old and weak RBC’s/production of RBCs and WBCs.

Question 2

Name the following:

(a) The cells which transport oxygen to the different parts of the human body.

(b) The cells that initiate blood clotting.

Answer 2

(a) Red Blood Cells

(b) Blood Platelets

Question 3

Name the following:

(a) Any one vein which starts from an organ and ends in another organ besides the heart.

(b) The kind of blood vessels which have no muscular walls.

(d) The kind of blood cells which can squeeze out through the walls of one category of blood vessels.

(e) The smallest common blood vessels formed by the union of capillaries.

(f) The category of blood vessels which start from capillaries and end in capillaries.

(g) The phase of the cardiac cycle in which the auricles contract.

(h) The valve present in between the chambers on the right side of the human heart.

(i) The phase of the cardiac cycle in which the ventricles get filled with blood from the atrium.

(j) The fluid found between the membranes of the heart.

Answer 3

(a) Hepatic portal vein

(b) Blood Capillaries

(d) White blood cells

(e) Venules

(f) Portal vein

(g) Atrial systole

(h) Tricuspid valve

(i) Atrial systole

(j) Pericardial fluid

Question 4

Complete the following statements by filling in the blanks from the choices given in the brackets.

(a) The blood vessel that begins and ends in capillaries is the ______. (hepatic artery, hepatic portal vein, hepatic vein)

(b) A blood vessel which has small lumen and thick wall is _______. (capillary, lymphatic duct, artery, venule)

(c) The valve which prevents the back flow of blood in the veins and lymph vessels ______.(mitral valve, tricuspid valve, semilunar valve)

(d) An anticoagulant present in the blood is _______.(heparin, hirudin, thromboplastin, calcium)

Answer 4

(a) The blood vessel that begins and ends in capillaries is the hepatic portal vein.

(b) A blood vessel which has small lumen and thick wall is artery.

(d) An anticoagulant present in the blood is heparin.

Question 5

Note the relationship between the first two words and suggest the suitable word/words for the fourth place:

(a) Lubb: Atrio-ventricular valve:: Dup:_______

(b) Coronary artery: Heart::Hepatic artery:______

Answer 5

(a) Lubb: Atrio-ventricular valve:: Dup: Semilunar valves

(b) Coronary artery: Heart::Hepatic artery: Liver

Question 6

Given reason, why a matured mammalian erythrocyte lacks nucleus and mitochondria?

Answer 6

A matured mammalian erythrocyte lacks a nucleus and mitochondria. The lack of a nucleus increases the surface area-volume ratio of RBCs, thus increasing the area for oxygen absorption. Also, the lack of a nucleus reduces the size of the cell, making it easy to flow through the blood vessels and more cells can be accommodated in a small area.

The lack of mitochondria implies that the cell does not use any oxygen absorbed for respiration, thus increasing the efficiency of the cell to transport oxygen as all the oxygen absorbed is transported without any loss.

C. SHORT ANSWER TYPE

Circulatory System Chapter 8 Biology

Question 1

Enumerate the structural differences between white blood cells and red blood cells.

Answer 1

Structural Differences between White Blood Cells and Red Blood Cells:

White Blood Cells	Red Blood Cells
1. White blood cells are amoeboid.	Red blood cells are minute biconcave disc-like structures.
2. They are nucleated cells.	They anucleated cells.
3. Haemoglobin is absent in red blood cells.	Haemoglobin is present in red blood cells.

Question 2

Why is it necessary to know the blood groups before giving transfusion?

Answer 2

During blood transfusion it is necessary to know the blood groups before transfusion because it is important that the blood groups of the donor and the recipient are compatible. In case of an incompatible blood transfusion, the recipient develops antibodies that attack the antigens present on the RBCs of the donor causing the blood cells to clump together which may result in death.

Question 3

Differentiate between members of each of the following pairs with reference to phrases in brackets:

(a) Antibodies and Antibiotics (Source)

(b) RBC and WBC (Structure)

(d) Erythrocytes and leucocytes (function)

(e) Artery and vein (direction of blood flow)

(f) Artery and vein (type of blood primarily flowing through)

(g) Tricuspid and bicuspid valves (location)

Answer 3

(a)

Differences between antibodies and antibiotics based on their source:

Antibodies	Antibiotics
They are produced by lymphocytes in response to the entry of pathogens in the bloodstream.	They are the medicines extracted from some bacteria and fungi. Antibiotics destroy or inhibit the growth of pathogens.

(b)

Differences between RBC and WBC based on their structure:

RBC	WBC
It is enucleated, biconcave, disc-like structure, flat in the centre while thick and rounded at the periphery.	It is nucleated and amoeboid in shape.

(c)

Differences between serum and vaccine based on their composition:

Serum	Vaccine
The plasma from which the protein fibrinogen has been removed is called serum.	Vaccine is killed or living weakened germs which are introduced in the body to stimulate the production of antibodies against pathogens for a particular disease.

(d)

Differences between erythrocytes and leucocytes based on their function:

Erythrocytes	Leucocytes
They function in the transport of oxygen throughout the body and in the removal of carbon dioxide from the body.	They help in the defense of the body against disease-causing pathogens.

(e)

Differences between artery and vein based on the direction of blood flow:

Artery	Vein
It carries blood away from the heart.	It brings blood towards the heart.

(f)

Differences between artery and vein based on the type of blood primarily flowing through them:

Artery	Vein
It generally contains oxygenated blood.	It generally carries deoxygenated blood.

(g)

Differences between tricuspid valve and bicuspid valve based on their location:

Tricuspid valve	Bicuspid valve
It is located between the right atrium and right ventricle of the heart.	It is located between the left atrium and left ventricle of the heart.

Question 4

What does the term double circulation mean?

Answer 4

Blood flows twice in the heart before it completes one full round. The full round thus includes pulmonary and systemic circulation. In pulmonary circulation, blood enters the lungs through pulmonary arteries. Pulmonary veins collect the blood from the lungs and carry it back to the left atrium.

In systemic circulation, blood from the left ventricle enters the aorta through which the blood is sent to the body parts. From the body parts blood is collected by veins and sent back to the heart. Therefore, the blood circulation in the human body is called double circulation.

Question 5

When are the sounds “LUBB” and “DUP” produced respectively during heart beat?

Answer 5

The first sound LUBB is produced when the atrio-ventricular valves i.e. tricuspid and bicuspid valves close at the start of ventricular systole.

The second sound DUP is produced at the beginning of ventricular diastole, when the pulmonary and aortic semilunar valves close.

Question 6

Why do people have a common belief that the heart is located on the left side of the chest?

Answer 6

People have a common belief that the heart is located on the left side of the chest because the narrow end of the roughly triangular heart is pointed to the left side and during its working the contraction of the heart is more powerful on the left side which can be felt.

Question 7 match

	Column B
(a) SA node	Plasma
(b) Defective haemoglobin in RBC	Serum
(c) Muscle fibres located in the heart	Pacemaker
(d) The liquid squeezed out of blood during clotting	Sickle cell anemia
(e) Never tires, keep on contracting and relaxing	Purkinje fibres
(f) Cardiac cycle	Cardiac muscles
(g) Liquid part of the blood without corpuscles	0.85 sec

Answer 7

Column A	Column B
(a) SA node	Pacemaker
(b) Defective hemoglobin in RBC	Sickle cell anemia
(c) Muscle fibres located in the heart	Purkinje fibres
(d) The liquid squeezed out of blood during clotting	Serum
(e) Never tires, keep on contracting and relaxing	Cardiac muscles
(f) Cardiac cycle	0.85 sec
(g) Liquid part of the blood without corpuscles	Plasma

Question 8

The table below is designed to indicate the transport of certain substances in our body. Fill in the blanks with suitable answers.

Substance	From	To
1. —–	Lungs	Whole body
2. Carbon dioxide	—–	—–
3. Urea	—–	—–
4. Digested carbohydrates	Intestines	—–
5. —–	—–	Target organs

Answer 8

Substance	From	To
1. Oxygen	Lungs	Whole body
2. Carbon dioxide	Whole body	Lungs
3. Urea	Whole body	Kidneys
4. Digested carbohydrates	Intestine	Whole body
5. Hormones	Endocrine glands	Target organs

D. LONG ANSWER TYPE

Selina Concise Biology Circulatory System Chapter 8

Question 1

What are the functions of blood plasma?

Answer 1

The functions of blood plasma are:

(a) Transports of digested food from the alimentary canal to tissues.

(b) Transports excretory materials from tissues to excretory organs.

(d) Distributes heat in the body to maintain the body temperature.

Question 2

What are the main steps in coagulation of blood in their correct sequence?

Answer 2

Blood clotting or coagulation occurs in a series of the following steps:

(a) The injured tissue cells and the platelets disintegrate at the site of wound to release thromboplastin.

(b) The thromboplastin with the help of calcium ions converts inactive prothrombin into active thrombin.

(c) Thrombin in the presence of calcium ions converts soluble fibrinogen into insoluble fibrin which forms a mesh or network at the site of wound.

(d) The blood cells trapped in this network shrink and squeeze out the plasma to leave behind a solid mass known as the clot.

Question 3

What are the following?

(a) Rh factor

(b) Universal donor

Answer 3

(a) Rh factor – It is an inherited antigen often found on the blood cells. Some individuals have these antigens and are thus Rh positive (Rh+) while others who do not have this antigen are Rh negative (Rh-).

(b) Universal donor – The person with blood group O is a universal donor as this type of blood can be given to persons with any blood group i.e. O, A, B, AB.

Question 4

Is it possible for the blood to clot under the skin? Give reason in support of your answer.

Answer 4

Blood clotting is not dependent on the exposure of blood to air. In fact, clotting can be caused by the movement of blood over a rough surface such as on cholesterol deposit inside of a blood vessel of the skin.

Question 5

State any five functions of the blood.

Answer 5

The functions of the blood are:

(a) Transport of digested food from the alimentary canal to tissues. These substances are simple sugars like glucose, amino acids, vitamins, mineral salts, etc.

(b) Transport of oxygen in the form of an unstable compound ‘oxyhaemoglobin’ from the lungs to the tissues.

(d) Transport of excretory materials from the tissues to the liver, kidney or the skin for elimination.

(e) Distribution of hormones from glands to the target sites.

(f) Distribution of heat to keep the body temperature uniform.

Question 6

Explain the following terms:

(a) Endothelium

(b) Lymph nodes

(d) Diastole

Answer 6

(a) Endothelium– It is the innermost layer of the muscular wall of an artery or a vein which faces the lumen.

(b) Lymph nodes– The structures from which fresh lymph channels arise which pour the lymph into major anterior veins.

(d) Diastole– The relaxation of muscles of ventricles or atria.

Question 7

Give the structural differences between an artery and a vein.

Answer 7

Artery	Vein
An artery is a vessel which carries blood away from the heart towards any organ.	A vein is a vessel which conveys the blood away from an organ towards the heart.
Artery has thick muscular walls.	Vein has thin muscular walls.
It has a narrow lumen.	It has a broad lumen.
There are no valves.	Thin pocket-shaped valves are present in the veins.
Arteries progressively decrease in size and branch to form arterioles. Arterioles further breaks up to form capillaries.	Capillaries unite to form branches called Venules. Venules further unite to form veins.

Question 8

What are the functions of tonsils and spleen?

Answer 8

Tonsils: Tonsils are lymph glands located on the sides of the neck. They tend to localize the infection and prevent it from spreading it in the body as a whole.

Spleen: The spleen is a large lymphatic organ. The spleen acts as a blood reservoir in case of emergency such as haemorrhage, stress or poisoning. It produces lymphocytes and destroys worn out RBCs.

Question 9

How do you account for the following differences?

(a) The left ventricle has thicker walls than the right ventricle.

(b) The walls of the right ventricle are thicker than those of the right auricle.

Answer 9

(a) The left ventricle pumps blood to the farthest points in the body such as the feet, the toes and the brain against the gravity while the right ventricle pumps the blood only up to the lungs. Therefore, the left ventricle has thicker walls than the right ventricle.

(b) The right ventricle pumps blood to the lungs for oxygenation whereas the right auricle receives the blood from vena cavae and passes it to the right ventricle. Therefore, walls of the right ventricle are thicker than those of the right auricle.

Question 10

Give reason for the following:

(a) The walls of the left ventricle are thicker than the walls of all the chambers.

(b) Blood flowing away from the stomach and intestines is put into circulation via the liver and not directly.

(d) Only the veins and not the arteries are provided with valves.

(e) Atrial wall is less muscular than the ventricular wall.

(f) The arteries are deep seated in the body.

Answer 10

(a)

The left ventricle pumps blood to the farthest points in the body such as the feet, the toes and the brain against the gravity. Thus, it requires greater force to push the blood. In order to with stand with the force applied the walls of the left ventricle are thicker than the walls of all the chambers.

(b)

The blood from stomach and intestines enters the liver via hepatic portal vein because the liver monitors all the substances that have to be circulated in body. The excess nutrients such as glucose, fats are stores in the liver. Excess amino acids are broken down by the process deamination. Toxic substances are detoxified.

(c)

During blood transfusion it is important that the blood groups of the donor and the recipient are compatible. In case of an incompatible blood transfusion, the recipient develops antibodies that attack the antigens present on the RBCs of the donor causing the blood cells to clump together which may result in death. The examination of Rh factor is also necessary for the blood transfusion. Therefore, the blood groups of both the donor and recipient must be known before transfusing blood.

(d)

Veins carry the blood from the body part towards the heart while the arteries carry the blood from the heart. Veins carry the blood against the force of gravity. Therefore, only the veins and not the arteries are provided with valves.

(e)

Atrial wall is less muscular than the ventricular wall because the major function of atria is to receive blood from the body and pump in into very next ventricles. While the ventricles pump the blood out of the heart. Right ventricle to the lungs and the left ventricle to all the body parts.

(f)

Arteries are responsible to carry oxygenated blood from the heart to the tissues. The blood flows in the artery under high pressure and in spurts. If arteries are located superficially then there is a high possibility of their damage which could lead to a lot of blood loss. To prevent this damage and blood loss, the arteries are deep seated in the body.

Question 11

What is meant by the term ‘double circulation’ of blood in mammals? What is diastole?

Answer 11

Blood flows twice in the heart before it completes one full cycle. This process of blood circulation in the human body is called double circulation.The expansion or relaxation phase of the atria is called a diastole.

Circulatory System Chapter 8 Concise Biology Solution for ICSE Class-10

Question 1

Given below is a diagram of a smear of human blood. Study the same and answer the questions that follow:

(a) Name the parts 1, 2, 3 and 4 indicated by guidelines.

(b) Mention two structural differences between the parts labeled 1 and 2.

(d) What is the life span of the part labeled “1”?

(e) Name a soluble protein found in “4” which helps in clotting of blood.

Answer 1

(a) 1 → Red Blood Cell (RBC),

2 → White Blood Cell (WBC),

3 → Blood Platelet

4 → Blood Plasma.

(b) The red blood cells are minute biconcave disc-like structures whereas the white blood cells are amoeboid.

(c) Function of part 1 (RBC): Transport of respiratory gases to the tissues and from the tissues, transport of nutrients from the alimentary canal to the tissues.

Function of part 2 (WBC): WBCs play major role in defense mechanism and immunity of the body.

Function of part 3 (Blood Platelet): Blood platelets are the initiator of blood clotting.

(d) The average life span of a red blood cell (RBC) is about 120 days.

(e) Thromboplastin

Question 2

Given below is a highly schematic diagram of the human blood circulatory system.

(a) Which part (state the number) represents the heart? Give reason in support of your answer.

(b) Which numbers represent the following respectively?

Aorta

Hepatic portal vein

Pulmonary artery

Superior vena cava

Renal vein

Stomach

Answer 2

(a) The structure 3 represents the heart. It forms the centre of double circulation and is located between the liver and the head (as per the diagram). Also the blood circulation (indicated by 1) begins from heart to lungs.

(b)

Aorta	5
Hepatic portal vein	7
Pulmonary artery	1
Superior vena cava	9
Renal vein	8
Stomach	10

Question 3

The diagram below shows part of the capillary bed in an organ of the human body. Some of the blood arriving at the capillaries at points labeled A, moves out into the spaces between the tissue cells. Study the diagram and answer the questions that follow:

(a) When the liquid from the blood surrounds the cells, what is it called?

(b) Name any one important component of the blood which remains inside the capillaries and fails to move out into the spaces.

(c) Some of the liquid surrounding the cells does not pass directly back into the blood but eventually reaches it by another route through vessel X. name the fluid present in vessel X.

(d) State two important functions performed in our body by the fluid present in vessel X.

Answer 3

(a) Tissue Fluid

(b) Red blood cells

(d) The lymph supplies nutrition and oxygen to those parts where blood cannot reach. The lymph drains away excess tissue fluids and metabolites and returns proteins to the blood from tissue spaces.

Question 4

The following simplified diagram refers to the outline plan of the circulation of blood in a mammal. Study the diagram and write the number and name of the blood vessel in each case as mentioned ahead.

(a) Several hours after a meal containing a lot of protein, which vessel will contain the highest concentration of urea?

(b) Which vessel would contain the highest concentration of amino acids and glucose soon after a meal?

Answer 4

(a) Hepatic portal vein (4)

(b) Hepatic portal vein (4)

Question 5

The figures given below show diagrammatic cross-sections of three kinds of blood vessels.

(a) Identify the blood vessels A, B and C.

(b) Name the parts labeled 1-4.

(d) Name the kinds of blood that flow through A and through B respectively.

(e) In which one of the above vessels referred to in (a) above does the exchanges of gases actually take place?

Answer 5

(a) A- Artery, B-Vein, C-Capillary

(b) 1 – External layer made of connective tissue

2 – Lumen

3 – Middle layer of smooth muscles and elastic fibres

4 – Endothelium

(c) An artery has thick muscular walls and a narrow lumen. It does not have any valve. A vein on the other hand has thin muscular walls and a wider lumen. It has valves to prevent backflow of blood.

(d) A (Artery)- Oxygenated blood, B (Vein)- Deoxygenated blood

(e) At the capillary level the actual exchange of gases takes place.

Question 6

The diagram given below represents the human heart in one phase of its activity. Study the same and then answer the questions that follow:

(a) Name the phase

(b) Which part of the heart is contracting in this phase? Give a reason to support your answer.

(d) What type of blood flows through the parts marked ‘1’ and ‘2’?

(e) How many valves are closed in this phase?

Answer 6

(a) Atrial Diastole and Ventricular Systole

(b) Ventricular muscles are contracting during this phase because the valves between the two ventricles and pulmonary artery and aorta are open while the atrio-ventricular valves are closed.

(c)

1	Pulmonary Artery
2	Aorta
3	Pulmonary Vein
4	Left Atrium
5	Bicuspid Valve
6	Right Ventricle

(d) Part 1 (Pulmonary artery) → Deoxygenated blood

Part 2 (Aorta) → Oxygenated Blood

(e) Two i.e., bicuspid and tricuspid valves are closed in this phase.

Question 7

Study the following diagram carefully and then answer the questions that follow:

(a) Name the cell labelled 1.

(b) Identify the phenomenon occurring in A.

(d) Name the process occurring in B and C and state the importance of this process in the human body.

Answer 6

(a) Atrial Diastole and Ventricular Systole

(b) Ventricular muscles are contracting during this phase because the valves between the two ventricles and pulmonary artery and aorta are open while the atrio-ventricular valves are closed.

(c)

1	Pulmonary Artery
2	Aorta
3	Pulmonary Vein
4	Left Atrium
5	Bicuspid Valve
6	Right Ventricle

(d) Part 1 (Pulmonary artery) → Deoxygenated blood

Part 2 (Aorta) → Oxygenated Blood

(e) Two i.e., bicuspid and tricuspid valves are closed in this phase.

Question 7

Study the following diagram carefully and then answer the questions that follow:

(a) Name the cell labelled 1.

(b) Identify the phenomenon occurring in A.

(d) Name the process occurring in B and C and state the importance of this process in the human body.

Answer 7

(a) 1 – Red blood cell

(b) Diapedesis

RBC	WBC
They lack a nucleus.	It have a nucleus.
They are biconcave and disc-shaped.	It has a spherical and have different sizes.

(d) The process which occurs in B and C is phagocytosis. In this process, the WBCs engulf the foreign particles and destroy them, thus preventing the occurrence of disease.

Question 8

Given below is a diagrammatic representation of certain types of blood vessels in human body.

(a) Identify the types of blood vessels numbered 1 to 5.

(b) Where can such an arrangement be found as an example – in lungs or in heart walls?

Answer 8

(a)1 – Arteriole

2 – Artery

3 – Venule

4 – Capillaries

5 – Vein

(b) Such an arrangement can be observed in the lungs.

Bottom of Form 2

lass-10 Concise Chemistry

Selina Solutions Chapter-2

Question 1

How do atoms attain noble gas configuration?

Answer 1

Atoms lose, gain or share electrons to attain noble gas configuration.

Question 2

Define

(a) a chemical bond

(b) an electrovalent bond

Answer 2

(a) A chemical bond may be defined as the force of attraction between any two atoms, in a molecule, to maintain stability.

(b) The chemical bond formed between two atoms by transfer of one or more electrons from the atom of a metallic electropositive element to an atom of a non-metallic electronegative element is called as electrovalent bond.

(c) The chemical bond formed due to mutual sharing of electrons between the given pairs of atoms of non-metallic elements is called as a covalent bond.

Question 3

What are the conditions for formation of an electrovalent bond?

Answer 3

Conditions for formation of Ionic bond are:

(i) The atom which changes into cation should possess 1, 2 or 3 valency electrons. The other atom which changes into anion should possess 5, 6 or 7 electrons in the valence shell.

(ii) A high difference of electronegativity of the two atoms is necessary for the formation of an Ionic bond.

(iii) There must be an overall decrease in energy i.e., energy must be released.

For this an atom should have low value of Ionisation potential and the other atom should have high value of electron affinity.

(iv) Higher the lattice energy, greater will be the case of forming an ionic compound.

Question 4

An atom X has three electrons more than noble gas configuration. What type of ion will it form? Write the formula of its (i) Sulphate (ii) Nitrate (iii) Phosphate (iv) carbonate (v) Hydroxide

Answer 4

It will form a cation: X³⁺

(i) X₂(SO₄)₃

(ii) X(NO₃)₃

(iii) XPO₄

(iv) X₂(CO₃)₃

(v) X(OH)₃

Question 5

Mention the basic tendency of an atom which makes it combine with other atoms.

Answer 5

Atoms combine with other atoms to attain stable octet or noble gas configuration.

Question 6

A solid is crystalline, has a high melting point and is water soluble. Describe the nature of the solid.

Answer 6

The crystalline solid is ionic in nature. It has strong electrostatic forces of attraction between its ions, which cannot be separated easily.

Crystalline solids have high melting and boiling points, and a large amount of energy is required to break the strong bonding force between ions.

Water is a polar compound, so it decreases the electrostatic forces of attraction in the crystalline solid, resulting in free ions in the aqueous solution. Hence, the solid dissolves.

Question 7

In the formation of compound XY_2,an atom X gives one electron to each Y atom, what is the nature of bond inXY₂? Draw the electron dot structure of this compound?

Answer 7

X and Y form an ionic bond in XY₂.

Question 8

An atom has 2, 8, 7 electrons in its shell. It combines with Y having 1 electron in its outermost shell.

(a) What type of bond will be formed between X and Y?

(b) Write the formula of compound formed.

Answer 8

(a) X has 7 electrons in its outermost shell and Y has only one electron in its outermost shell so Y loses its one electron and X gains that electron to form an ionic bond.

(b) The formula of the compound would be XY.

Question 9

Draw electron dot diagrams of

(i) NaCl (ii) MgCl₂(iii) CaO.

Answer 9

Orbit structure and electron dot diagram of NaCl:

Orbit structure and electron dot diagram of MgCl₂:

Electron dot Orbit structure diagram of CaO:

Question 10

Compare :

(a) Sodium atom and sodium ion

(b) Chlorine atom and chlorine ion

With respect to

(i) Atomic structure

(ii) Electrical state

(iii) Chemical action and

(iv) toxicity

Answer 10

(a) Sodium atom and sodium ion

(i) Sodium atom has one electron in M shell while sodium ion has 8 electrons in L shell.

(ii) Sodium atom is neutral while sodium ion is positively charged.

(iii) Sodium atom is highly reactive while its ion is inert.

(iv)Sodium atom is poisonous while sodium ion is non-poisonous.

(b)Chlorine atom and chlorine ion

(i) Chlorine atom has 7 electrons in its M shell while Chloride ion has 8 electrons in the same shell.

(ii) Chlorine atom is neutral while chloride ion is negatively charged.

(iii) Chlorine atom is highly reactive while its ion is inert.

(iv)Chlorine gas is poisonous while chloride ion is non-poisonous.

Question 11

The electronic configuration of fluoride ion is the same as that of a neon atom. What is the difference between two?

Answer 11

Fluoride ion is negatively charged while neon atom is neutral.

Question 12

(a) What do you understand by redox reactions? Explain oxidation and reduction in terms of loss or gain of electrons. (b) Divide the following redox reactions into oxidation and reduction half reactions.

(c) Potassium (Atomic No. 19) and chlorine (Atomic No. 17) react to form a compound. On the basis of electronic concept, explain

(i) oxidation (ii) reduction (iii) . oxidising agent (iv) reducing agent

Answer 12

(a) Transfer of electron(s) is involved in the formation of an electrovalent bond. The electropositive atom undergoes oxidation, while the electronegative atom undergoes reduction. This is known as redox process.

Oxidation: In the electronic concept, oxidation is a process in which an atom or ion loses electron(s).

Zn → Zn²⁺+ 2e^–

Reduction: In the electronic concept, the reduction is a process in which an atom or ion accepts electron(s).

(b) Cu²⁺ + 2e^–→ Cu

(i) Zn → Zn²⁺+ 2e^– (Oxidation)

Pb²⁺+ 2e^–→ Pb (Reduction)

(ii) Zn → Zn²⁺+ 2e^– (Oxidation)

Cu²⁺+ 2e^–→ Cu (Reduction)

(iii). Cl₂ + 2e^–→ 2Cl^– (Reduction)

2Br^–→ Br₂ + 2e^–(Oxidation)

(iv) Sn²⁺→ Sn⁴⁺ + 2e^– (Oxidation)

2Hg²⁺+ 2e^–→ Hg₂(Reduction)

(v) Cu⁺→ Cu²⁺+ e^–(Oxidation)

Cu⁺+ e^–→ Cu (Reduction)

(i) Oxidation: In the electronic concept, oxidation is a process in which an atom or ion loses electron(s).

K → K⁺+ e^–

(ii) Reduction: In the electronic concept, the reduction is a process in which an atom or ion accepts electron(s).

Cl₂ + 2e^–→ 2Cl^–

(iii) Oxidising agent

An oxidising agent oxidises other substances either by accepting electrons or by providing oxygen or an electronegative ion, or by removing hydrogen or an electropositive ion.

Cl₂ + 2e^–→ 2Cl^–

(iv) Reducing agent

A reducing agent reduces other substances either by providing electrons or by providing hydrogen or an electropositive ion, or by removing oxygen or an electronegative ion.

K → K⁺+ e^–

ICSE Chemistry Class-10 Concise Selina Solution

Chemical Bonding Chapter 2 Intex 2

Question 1

What are conditions necessary for the formation of covalent molecules?

Answer 1

(i) Both atoms should have four or more electrons in their outermost shells, i.e., non-metals.

(ii) Both the atoms should have high electronegativity.

(iii) Both the atoms should have high electron affinity and high ionisation potential.

(iv) Electronegativity difference between the two atoms should be zero or negligible.

(v) The approach of the atoms towards one another should be accompanied by decrease of energy.

Question 2

Elements A, B and C have atomic numbers 17, 19 and 10 respectively.

(a) State which one is:

(i) A non-metal

(ii) A metal

(iii) Chemically inert?

(b) Write down the formula of the compound formed by two of the above elements.

Answer 2

(a) A is a non-metal; B is a metal while C is a chemically inert element.

(b) BA

Question 3

Draw the electron dot diagram and structure of:

(a) nitrogen molecule

(b) magnesium chloride

Answer 3

Question 4

What is the difference between:

(a) Ionic compounds and polar covalent compounds

(b) Ionic compounds and covalent compounds

Answer 4

(a) difference between Ionic compounds and polar covalent compounds

Ionic compounds are formed as a result of the transfer of one or more electrons from the atom of a metallic electropositive element to an atom of a non-metallic electronegative element.

A polar covalent compound is the one in which there is an unequal distribution of electrons between the two atoms.

(b) difference between Ionic compounds and covalent compounds

Ionic compounds, made up of ions, are generally crystalline solids with high melting and boiling points.

They are soluble in water and good conductors of electricity in aqueous solution and molten state.

Covalent compounds, made up of molecules, can exist as soft solids or liquids or gases with low melting and boiling points. They are generally insoluble in water and poor conductors of electricity.

Polar covalent compounds are formed between 2 non-metal atoms that have different electronegativities and therefore have unequal sharing of the bonded electron pair.

Non-polar compounds are formed when two identical non-metals equally share electrons between them.

Question 5

The element X has electronic configuration 2, 8, 18, 8, 1. Without identifying X ,

(a) Predict the sign and charge on a simple ion of X

(b) Write if X will be an oxidizing agent or reducing agent and why?

Answer 5

(a) X⁺

(b) X will be a strong reducing agent as it will have the tendency to donate its valence electron.

Question 6

What do you understand by polar covalent compounds? Explain it by taking hydrogen chloride as an example.

Answer 6

Covalent compounds are said to be polar when shared pair of electrons are unequally distributed between the two atoms. For example in HCl, the high electronegativity of the chlorine atom attracts the shared electron pair towards itself. As a result, it develops a slight negative charge and hydrogen atom develops a slight positive charge. Hence, a polar covalent bond is formed.

Question 7

(a) Explain the bonding in methane molecule using the electron dot structure.

(b) The methane molecule is a non-polar molecule. Explain.

Answer 7

(a)

Atom	Electronic configuration	Nearest noble gas	To attain stable electronic configuration of a nearest noble gas
Carbon	¹²₆C [2,4]	Neon [2,8]	Carbon needs four electrons to complete the octet.
Hydrogen	¹₁H [1]	Helium [2]	Hydrogen needs one electron to complete the duplet.

One atom of carbon shares four electron pairs, one with each of the four atoms of hydrogen.

Before combination

(4 [H] and 1 [C] atom)

After combination (CH₄ – Methane molecule)

(b) Methane is a covalent compound and is non-polar in nature. This is because the shared pair of electrons is equally distributed between the two atoms. So, no charge separation takes place and the molecule is symmetrical and electrically neutral.

Question 8

Give the characteristic properties of:

(a) Electrovalent compounds

(b) Covalent compounds

Answer 8

(a) Properties of Electrovalent Compounds:

1. Ionic compounds usually exist in the form of crystalline solids.

2. They have high melting and boiling points.

3. These compounds are generally soluble in water but insoluble in organic solvents.

4. They are good conductors of electricity in the fused or in an aqueous solution state.

(b) Properties of Covalent Compounds:

1.The covalent compounds exist as gases or liquids or soft solids.

2. The melting and boiling points of covalent compounds are generally low.

3. Covalent compounds are insoluble in water but dissolve in organic solvents.

4. They are non-conductors of electricity in the solid, molten or aqueous state.

Question 9

(a) State the type of bond is formed when the combining atoms have:

(i) zero E.N. difference

(ii) small E.N. difference

(iii) large E.N. difference

1. State the type of bond formed, and draw Lewis structure of

2. water

3. calcium oxide

Answer 9

(a)

(i) Covalent bond

(ii) Polar covalent bond

(iii). Ionic bond

(b)

(i) water: Polar covalent bonding takes place in water.

(ii) calcium oxide: Electrovalent bonding takes place in calcium oxide.

Question 10

Explain the following:

(a) Electrovalent compounds conduct electricity.

(b) Electrovalent compounds have a high melting point and boiling point, while covalent compounds have low melting and boiling points.

(d) Electrovalent compounds are usually hard crystals yet brittle.

(e) Polar covalent compounds conduct electricity.

Answer 10

(a) Electrovalent compounds

are good conductors of electricity in the fused or aqueous state because electrostatic forces of attraction between ions in the solid state are very strong and these forces weaken in the fused state or in the solution state. Hence, ions become mobile.

(b) Electrovalent compounds

have a strong force of attraction between the oppositely charged ions, so a large amount of energy is required to break the strong bonding force between ions. So, they have high boiling and melting points.

Covalent compounds have weak forces of attraction between the binding molecules, thus less energy is required to break the force of binding. So, they have low boiling and melting points.

(c) As water is a polar compound, it decreases the electrostatic forces of attraction, resulting in free ions in the aqueous solution. Hence, electrovalent compounds dissolve.

Covalent compounds do not dissolve in water but dissolve in organic solvents. Organic solvents are non-polar; hence, these dissolve in non-polar covalent compounds.

(d) Electrovalent compounds

are usually hard crystals yet brittle because they have strong electrostatic forces of attraction between their ions which cannot be separated easily.

(e) Polar covalent compounds conduct electricity because they form ions in their solutions.

Question 11

Elements X, Y and Z have atomic numbers 6, 9 and 12, respectively. Which one

(a) forms an anion

(b) forms a cation

Answer 11

(a)

(i) Y = 9

(ii) Z = 12

(b) Ionic bond with molecular formula ZY₂.

Question 12

Taking MgCl₂ as an electrovalent compound and CCl₄ as a covalent compound, give four differences between electrovalent and covalent compounds.

Answer 12

MgCl₂ – Electrovalent compound	CCl₄ – Covalent compound
hard crystalline solids consisting of ions.	gases or liquids or soft solids.
high melting and boiling points.	low melting and boiling points.
conduct electricity in the fused or aqueous state.	do not conduct electricity in the solid, molten or aqueous state.
It is soluble in inorganic solvents but insoluble in organic solvents.	It is insoluble in water but dissolve in organic solvents.

Question 13

Potassium chloride is an electrovalent compound, while hydrogen chloride is a covalent compound. But both conduct electricity in their aqueous solutions. Explain.

Answer 13

Potassium chloride is an electrovalent compound and conducts electricity in the molten or aqueous state because the electrostatic forces of attraction weaken in the fused state or in aqueous solution.

Polar covalent compounds like hydrogen chloride ionise in their solutions and can act as an electrolyte. So, both can conduct electricity in their aqueous solutions.

Question 14

(a) Name two compounds that are covalent when pure but produce ions when dissolved in water.

(b) For each compound mentioned above, give the formulae of ions formed in the aqueous solution.

Answer 14

(a) HCl and NH₃

(b) HCl + H₂O → H₃O⁺ + Cl^–

NH₃ + H₂O →NH₄⁺ + OH^–

Question 15

An element M burns in oxygen to form an ionic bond MO. Write the formula of the compounds formed if this element is made to combine with chlorine and sulphur separately.

Answer 15

Formula of compound when combined with sulphur – MSFormula of compound when combined with chlorine – MCl₂

Question 16

Element A has 2 electrons in its M shell. Element B has atomic number 7.

(a) Write equations to show how A and B form ions.

(b) If B is a diatomic gas, write the equation for the direct combination of A and B to form a compound.

(c) If the compound formed between A and B is melted and an electric current is passed through the molten compound, then element A will be obtained at the _________ and B at the ________ of the electrolytic cell.

Answer 16

(c) If the compound formed between A and B is melted and an electric current is passed through the molten compound, then element A will be obtained at the cathode and B at the anode of the electrolytic

Exercise-2

Question 1

Define a coordinate bond and give conditions for its formation.

Answer 1

The bond formed between two atoms by sharing a pair of electrons, provided entirely by one of the combining atoms but shared by both is called a coordinate bond. It is represented by an arrow starting from the donor atoms and ending in the acceptor atom.

Conditions:

1. One of the two atoms must have at least one lone pair of electrons.

2. Another atom should be short of at least a lone pair of electrons.

The two lone pair of electrons in the oxygen atom of water is used to form coordinate bond with the hydrogen ion which is short of an electron resulting in the formation of the hydronium ion.

H₂O + H⁺ H₃O⁺ Over here the hydrogen ion accepts one lone pair of electrons of the oxygen atom of water molecule leading to the formation of a coordinate covalent bond.

Question 2

What do you understand by lone pair and shared pair?

Answer 2

A pair of electrons which is not shared with any other atom is known as a lone pair of electrons. It is provided to the other atom for the formation of a coordinate bond.

A pair of electrons which is shared between two atoms resulting in the formation of a covalent bond is called a shared pair.

Question 3

State the type of bonding in the following molecules:

(a) Water

(b) Calcium oxide

(d) Methane

(e) Ammonium ion

(f) Ammonium chloride

Answer 3

(a) Polar covalent bond

(b) Ionic bond

(d) Covalent bond

(e) Coordinate bond

(f) Electrovalent bond, dative bond (or coordinate bond) and covalent bond

Question 4

(b) Give two examples in each case:

(i) Co-ordinate bond compounds

(ii) Solid covalent compounds

(iii) Gaseous polar compounds

(iv) Gaseous non-polar compounds

(v) Liquid non-polar compounds

Answer 4

(b)

(i) Ammoniumion and hydronium ion

(ii) Phosphoruspentachloride and diamond

(iii) Hydrogen chloride and water vapour

(iv) Oxygen gas and nitrogen gas

(v) Toluene and Gasoline

Question 5

Element M forms a chloride with the formula MCl₂which is a solid with high melting point. M would most likely be in the group in which ______ is placed. [(a) Na (b) Mg (c)Al (d) Si]

Answer 5

Answer-6

	Sodium	Phos- phorus	Carbon
Formula of chloride	NaCl	PCl₅	CCl₄
Nature of bonding	Ionic	Covalent	Covalent
Physical state of chloride	Solid	Solid	Liquid

Questions-6

(a) How many atoms of each kind are present in the following molecules: calcium oxide, chlorine, water, carbon tetrachloride?

(b) How many electrons are required by each atom mentioned in (a) to attain the nearest noble gas configuration?

Answer-6

(a) CaO- 1 calcium atom + 1 oxygen atom

Cl₂ – 2 chlorine atoms

H₂O – 2 hydrogen atoms + 1 oxygen atom

CCl₄ – 1 carbon atom + 4 chlorine atoms

(b) Ca – will donate two electrons

O – will accept two electrons

Cl – will accept one electron, so two Cl atoms will share an electron pair.

C – will accept four electrons by sharing electrons pairs with hydrogen forming covalent bonds.

H – will donate one electron by sharing an electron pair with carbon.

Question 8

Complete the following:

(a) When the nuclei of two reacting atoms are of _____ mass, then a bond so formed is called _____covalent bond. (Equal, unequal, polar, non -polar).

(b) In case of non-polar covalent bond, the covalent bond is formed in the _____of atoms and shared electrons are distributed _____. (Corner, middle, equally, unequally).

(d) The ions in ______ compounds are held very strongly due to strong _______ forces. ( electrovalent, covalent, electromagnetic, electrostatic) (2018)

Answer 8

(a) Unequal,polar

(b) Middle, equally

(d) Electrovalent, electrostatic

Question 9

(a) Compound X consists of molecules. Choose the letter corresponding to the correct answer from the options A, B, C and D given below:

(i) The type of bonding in X will be

A. ionic B. electrovalent C. covalent D molecular

(ii) X is likely to have a

A low melting point and high boiling point

B high melting point and low boiling point

C low melting point and low boiling point

D high melting point and high boiling point

(iii). In the liquid state, X will

A become ionic

B be an electrolyte

C conduct electricity

D not conduct electricity

Answer 9

(a)

(i) C

(ii) C

(iii) D

Question 10

(a) Electrons are getting added to an element Y:

(i) Is Y getting oxidised or reduced?

(ii) What charge will Y migrate to during the process of electrolysis?

(b) Acids dissolve in water and produce positively charged ions. Draw the structure of these positive ions.

Answer 10

(a)

(i) Y is getting reduced.

(ii) Y is positive and it will migrate towards negative electrode that is cathode.

(b)

Question 11

a. Elements Q and S react together to form an ionic compound. Under normal conditions, which physical state will the compound QS exist in?

b. Can Q and S both be metals? Justify your answer.

c. The property which is characteristic of an electrovalent compound is that

A. it is easily vaporised

B. it has a high melting point

C. it is a weak electrolyte

D. it often exists as a liquid

d. When a metal atom becomes an ion,

A. it loses electrons and is oxidised

B. it gains electrons and is reduced

C. it gains electrons and is oxidised

D. it loses electrons and is reduced

Answer 11

a. Solid

b. No, in the formation of an ionic compound, one element is a metal and the other is a non-metal.

c. B

d. A

Question 12

(a) In the formation of magnesium chloride (by direct combination between magnesium and chloride), name the substance that is oxidized and the substance that is reduced.

(b) What are the terms defined below?

(i) A bond formed by share pair of electrons, each bonding atom contributing one electron to the pair.

(ii) A bond formed by a shared pair of electrons with both electrons coming from the same atom.

Answer 12

(a) Magnesium oxidises and chlorine reduces during the formation of magnesium chloride.

(b) (i) Covalent bond

(ii) Co-ordinate bond

BIOLOGY 10 CLASS Chapter-pollution

A.Multiple Choice Type

1.(d)

2.(c)

3.(b)

B.Very Short Answer Type

1.(i)CO2,NO2

(ii)CFC's, Styrofoam

2.Matching

(a)--iv

(b)--iii

(c)--vi

(d)--v

(e)--ii

(f)--i

3.(i)particulate

(ii)X-rays

(iii)hot

(iv)domestic activities

4.Identify biodegradable waste

Peel off vegetables and fruits, grass, paper

C.Short Answer Type

1.(i)It leads increased growth of microorganisms thus decreasing level of oxygen in the river which lead to death of fish and other water animals. It also affect aquatic plants and leads to increase chemical oxygen demand and biological oxygen demand.

(ii) it leads to air pollution causing acid rain,respiratory disorder, deterioration of monuments. It also makes the soil acidic and less fertile.

(iii)DDT use in agriculture to destroy pest alter the basic structure of soil,kill microorganisms in IT army even reach the human body through food grown in such soils. It reduces soil fertility by killing microorganisms in the soil.

(iv)1. Interferes in communication

2. Lowers efficiency of work

2. It consists of kitchen wastes, toilet and other household waste water.

3.Oil spills are the accidental discharges of petroleum in oceans or estuaries. The sources of spills are the overturned oil tankers, offshore oil mining, oil refineries.

Effects

i. Soil pollution kills a lot of marine life.

ii. It make aquatic birds flightless.

4.i. Prohibiting blowing of horns.

ii. No to burn the firecrackers.

5.The Swachh Bharat Abhiyan is a significant cleanliness campaign started by the Government of India. It was officially launched on 2nd October 2014 by a Prime Minister Shri Narendra Modi.

Following are some objectives of the:

i. To clean the streets, roads and infrastructure of the countrie's cities and towns.

ii. To eliminate open defecation through the construction of toilets

iii. Establish an accountable mechanism of monitoring laterine use.

D.Descriptive type

(a)Pollution:-pollution is the addition of any such constituent in the environment which deteriorates its natural quality.

(b)Waste:-waste is any unwanted or undesired material or substance resulting from industrial, commercial mining, and agricultural operations, and from community activities.

(c)Air pollution:-Air pollution means degradation of the air quality which harmfully effects the living organisms as well as certain objects.

(d)Oil spills:-oil fields are the accidental discharges of petroleum in oceans or estuaries.

(e)Pesticides:-These are the chemicals which kills pests in agricultural farms, godowns and even at homes.

(f)Sanitary landfills:-Sanitary landfills are the places where the wastes are dumped in a ground depression and covered with dirt everyday.

(g)Noise:-noise is defined as any unpleasant and loud sound interfering with one hearing and concentration.

2.Distinguish between the following

(a)SEWAGE:-It is the liquid waste from domestic activities.

It consists of kitchen wastes toilet and other household waste water.

EFFLUENTS:-It is a liquid waste from lake and rivers

it consists of waste coming from factories and industries.

(b)BOIDEGRADABLE WASTE:-These are those substances which can be broken down by micro organisms into harmless and non toxic substances.

For example:-dung,leaves, kitchen left overs etc.

NON-BIODEGRADABLE WASTE:-These are those substances that cannot be broken down by microorganisms.

For example:-plastic, metallic cans, glass etc.

(c)SMOKE:-It consists of airborne particulate pollutants.

SMOG: Smog is the mixture of smoke and dust particles and small drops of fog.

E.STRUCRURED/APPLICATION SKILL

1.Oil spill, water pollution, thermal pollution,

2.(i) noise pollution

(ii) horns, vehicles, loud loudspeakers, aircrafts

(iii) Headache, irritation and loss of hearing

(

. To clean the streets, roads and infrastructure of the country's cities and towns.

3.(i)Ozone depletion

Certain gaseous compounds such as CFC released from refrigerators and packing material styrofom form rise into the atmosphere and their they breakdown in two chlorine atoms which in turn breakdown Ozone into oxygen O2 and O,this is known as ozone depletion.

(ii)Aerosols

(iii)Skin allergies,cancer and genetic disorders

4.(i)PM Sh.Narendra Modi on 2nd October 2014.

(ii)1.To clean the street route and its infrastructure of the country's cities and towns.

2. To eliminate open defecation through the construction of toilets.

3.To achieve efficient solid and liquid waste management system.

5.(i)Air pollution is degradation of the air quality which harmfully effects the living organisms as well as certain objects.

(ii)Gaseous pollution and particulate pollution.

(iii)Vehicular air pollution

For eg.Cars

Industrial air pollution

For eg.brick kilns

(iv)(a) efficient engines

(b) greater use of compressed natural gas.

(c)Installation of tall chimneys in factories.

5.(i)Soil pollution.

Degradation of the quality of soil by industries,chemical fertilizers,pesticides and acid rain.

(ii)1.Pesticides

2. Chemical fertilizers

3. Industrial waste

4. Biomedical waste

(iii) 1.Damage to vegetation by pollution of soil

2. Fish and other aquatic animals are harmed.

Class - X Geography Chapter 4

CLIMATE OF INDIA

1.The factors affecting the climates of a place are: -
i. Latitude
ii. Altitude
iii. Distance from the sea
iv. Varied Relief
2. India has Tropical monsoon type of climate
3.Charactristics of tropical monsoon type of climate are: -
i. Most of the country gets rainfall from the south west monsoons.
ii. It is unevenly distributed
iii. It is erratic and unpredictable.
iv. It is seasonal, mostly occur in rainy season.
v. It is orographic in nature.
vi. Monsoon rains have great impact on our economy.
4. The winds that blow from sea to land are called on-shore winds and the winds that blow from
land to sea are called off-shore winds.
5. Same as Ans.3
6. Kali Baisakhi, Loo, Mango showers
7. The more important branch is the Arabian sea branch because it gives rain
to most of the India.
8. Kerala
9. Same as Ans.3
10. i) The hot dry season (March to May)
ii)The rainy season (June to September)
iii)The season of retreating south-west monsoon (October to November)
iv) The cold season (December to February)
11. The word monsoon has been derived from the Arabic word `Mausim’ which means season.

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Class - X Geography Chapter 5

SOIL RESOURCES IN INDIA [10 Class]

Ans 1: Soil is formed under specific natural conditions. It is a mixture of minerals or inorganic matter which result from denudation and disintigration of rocks.
Ans 2 : Soil formation is related to the parent rock material, relief, climate and vegetation. Animals insects and man also play an important role in the formation of soil.
Ans 3 : soil is a mixture of inorganic material , minerals and organic material like humus.Inorganic components like silica,clay and chalk.
Ans 4 :The major soils are alluvial soils,black soils and red soils.
Ans 5 :Alluvial soils are very fertile because every year fresh sediments are deposited by rivers.
Ans 6 :Black soils are formed in situ i.e, formed where they are found.They are called residual soil. These soils have originated from solidification of basic lava spread over large area of deccan pleateau during volcanic activity.
Ans 7 : No black soil doesnot undergo leaching.
Ans 8 : The other name of black soils are Regur and black cotton soils
Characteristics :
1: Retains moisture and becomes sticky when wet .
2: Releases moisture during dry period.
Ans 9 : Red soil are not suitable for agriculture because it lacks lime,magnesia,phosphate,nitrogen and humus and are rich in potash and become fertile with proper use of fertilizers and irrigation
Ans 10 Leaching is a process in which the mineral nutrients are washed away making the top soil infertile. The example of a leached soil is laterite soil
Ans 11:Alluvial soil is widely distributed over the ganga basin.
Ans 12 : The most widely transported soil is the alluvial soil.
Ans 13 : Laterite soil is suitable for growing coffee in india .
Ans 14: Laterite soil is found on the summit of eastern ghats.
Ans 15: Mountain soil is rich in humus but deficient in phosphate ,potash and lime .
Ans 16: Desert soil is found in thse area which receive rainfall below 50 cm features.It contains low percentage of organic matter due to dry climate and absence of vegetation.Soil is alkaline is nature as there is no rainfall to wash soluble salt.
Ans 17 : Laterite soils are formed under condition of high temperature and heavy rainfall with alternate wet and dry period.
Ans 18 : Monsoon condition promote leaching of the soil i.e the heavy rainfall washes away the top soil containing silica.
Ans 19: Soil erosion is the removal of the top soil by different agents like wind and water.
Types :
[1] Splash erosion
[2] Sheet erosion
[3] Gully erosion
Ans 20 : Soil conservation is an effort made to prevent soil erosion or reduce the rate of soil erosion.
Ways to reduce erosion:
Aforestation, to check overgrazing and constructing dams and barrages.
Ans 21 : [1] Top soil –it is the uppermost layer of soil consisting of humus which is very fertile.
[2] In situ-the soil formed where they are found.
[3] Bhanger-it consist of old alluvium,contains kankar, pebbles and gravels and are dark in colour.
[4] Khadar-it consist of new alluvial,contain fine sand and clay and are pale brown in colour.
[5] Humus- it is dark organic material in soils produced by the decomposition of vegetables or animal matter and is essential to the fertility of the soil.

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NATURAL VEGETATION

Ans 1 Natural vegetation are plants that have not grown by human. It does not need human and gets whatever it needs from its natural environment

Ans 2Distribution of natural vegetation depend upon variation in the amount of rainfall and variation in relief

Ans3 Trees maintain ecological balance, reduce pollution, maintain humidity , purify air and are a source of timber fruits and fuel.

Ans 4 The percentage of forest cover in India on land is 21.02%.

Ans 5 The forest cover in india is shrinking-reasons are:

[1] Increased demand for forest products.

[2] Deforestation.

[3] Urbanisation\industrialisation.

[4] Over grazing by cattle.

[5] Faulty agricultural practices eg. Jhumming or shifting cultivation.

[6] Large multipurpose projects or river valley projects.

[7] Increasing population.

[8] Forest fire.

[9] Conservation of forest land to agricultural land.

[10] Demand for agricultural land.

PRECAUTIONS TAKEN:

[1] Van Mahotsava.

[2] Afforestation.

[3] Reafforestation.

Ans 6 : Major forest products are timber and wood.

Minor products are gum,tac and medicinal herbs.

Ans 7: There are two factors on which the type of natural vegetation and its distribution depend upon:

[1] Variation in amount of rainfall.

[2] Variation inn relief.

Ans 8: Charateristics of tropical evergreen forest:-

-They are found in the areas of heavy rainfall,they are also known as “rain forest”.

-The thick ground cover of the forest is characterized by climbers and epiphytes.Bamboo .

-and ferns are also common.

-They donot shed their leaves at the same time,they remain evergreen and hence named “tropical evergreen forest”

The important trees of these forests are rosewood, sisam and gurjan.

Ans 9 The economically most important vegetation belt of India is deciduous monsoon forest as they yield valueable timber and several other forest products.

Ans10 Deciduous forest are found in the belt running along the western ghats surrounding the belt of evergreen forest. The deciduous forests are found in arias of average temperature of about 24 degree to 27 degree celcius and average rainfall between 150-200 cm.

Ans 11 The trees found in monsoon forest are :

1 Teak- furniture, railway carriages

2 sal- railway sleeper,door and windows

3Myrobalan – tanning leather, dyeing cotton etc.

Ans12 The main feature of mountain forests are :

[1]It consist of mixed deciduous and coniferous forests

[2]They occur in the transition zone of mixed forest and coniferous forests

They are found in the temperate zone of the Himalayas, from Kashmir to assam at varying altitude. In the south, they are found in nilgiri and annumalai hillsat an elevation between 1000 m to 1500 m

Ans13 Desert and semi desert vegetation is found in the area of average temperature of 25 degree to 27 degree celcius and with a rainfall of less than 25 cm.

And 14 The characteristics of mangrove forests are:

[1] They have aerial, stilt like roots.

[2]They can be seen during low tide.

[3]Mangrove forests are characterized by breathing roots which act as respiratory organs.

Ans 15 The other names are tidal and littoral forests

Ans 16 Afforestation means planting of trees over a large area and deforestation means cutting of trees over large area.

Ans 17 The two characteristic features of tropical evergreen forests are:

[1]They are found in the areasof heavy rainfall.

[2]Trees are evergreen and do not shed their leaves.Dence undergrowth and lack of transport facilities make it difficult to exploit.

Ans 18 The deciduous forests are found in the areas of average temperatureof about 24 degree to 27 degree celciusand average rainfall between 150 to 200cm.

Ans 19 Thorn and scrub are found in Rajasthan, Punjab, western Utter Pradesh and Gujrat.Trees found here are khair,babool and khajuri.

Ans 20 Mangrove vegetation. The most important trees are sundry, hintal and gurjun.

Ans21 Sundri tree is hard , strong and durable.

Ans 22 Forest are grown in and around steel cities to reduce pollution and to provide raw material to the industry.

Ans 23 It is grown in Himachal Pradesh and Kashmir.It is used for making railway sleepers and House consruction

Ans 24 The type of vegetation is mangrove.

Ans 25 The total forest cover of the total geographic area of India is 21.02%.

Ans26 [a] As they do not shed their leaves and remain evergreen.

[b] As they are found in the areas of heavy rainfall.

[c]because there the temperature is26 to 29 degree celcius

Ans 27[a]coastal tidal forest

[b]myrabalon.

[c]deciduous monsoon forest

Ans 28 Social forestry- it create awareness regarding conservation of forest and to meet the need of the rural people regarding fuel and timber.

Agroforestry-it combines agricultural and forestry technologies to create more diverse,productive and profitable land use system.A narrow definition of agroforestry is “ trees on farms”.

Analytical Chemistry ICSE Class-10

Concise Selina Solutions Chapter-4

Intext Question Analytical Chemistry ICSE Class-10
Question 1
What do you understand by the following:
(i) Analysis,
(ii) Qualitative analysis,
(iii) Reagent,
(iv) Precipitation?
Answer 1
(i) Analysis: The determination of chemical components in a given sample is called analysis.
(ii) Qualitative analysis: The analysis which involves the identification of the unknown substances in a given sample is called qualitative analysis.
(iii) Reagent:A reagent is a substance that reacts with another substance.
(iv) Precipitation: It is the process of formation of an insoluble solid when solutions are mixed. The solid thus formed is called precipitate.
Question 2
Write the probable colour of the following salts:
(i) Iron (III) chloride,
(ii) Potassium nitrate,
(iii) Ferrous sulphate,
(iv) Aluminum acetate,
Answer 2
(i) Yellow
(ii) Colourless
(iii) Pale Green
(iv) Colourless
Question 3
Name the probable cations present in the following observations:
a.White precipitate insoluble in NH4OH but soluble in NaOH
b.Blue-coloured solution
Answer 3
(a) Pb2+
(b).Cu2+
Question 4
Name the metal hydroxides which are :
(i) Insoluble
(ii) Soluble
(a) Caustic soda solution
(b) Ammonium hydroxide solution.
Answer 4
Name of solution
Soluble metal hydroxides
Insoluble metal hydroxides
Caustic soda solution
Zn(OH)2
Pb(OH)2
Fe(OH)3
Ammonium hydroxide solution
Zn(OH)2
Cu(OH)2
Fe(OH)3
Fe(OH)2
Question 5
What do you observe when an ammonium salt is heated with caustic soda solution? Write the word equation.
Answer 5
When ammonium salt is heated with caustic soda solution, ammonia gas is evolved.
The word equation is:
Ammonium chloride + Sodium hydroxide PRIVATE "TYPE=PICT;ALT=" Sodium
chloride + water + ammonia
Ammonium sulphate + Sodium hydroxide Sodium sulphate + water + ammonia
The balance equation is:
NH4Cl+NaOH PRIVATE "TYPE=PICT;ALT=" NaCl+H2O+NH3↑
(NH4)2SO4 + 2NaOH Na2SO4 + 2H2O + 2NH3↑
Question 6
How will you distinguish NH4OH solution from NaOH solution?
Answer 6
NH4OH and NaOH can be distinguished by using calcium salts.
For example on adding NaOH to Ca(NO3)2, Ca(OH)2 is obtained as white precipitate which is sparingly soluble in excess of NaOH.
Ca(NO3)2+2NaOHCa(OH)2+2NaNO3
On addition of NH4OH to calcium salts, no precipitation of Ca(OH)2 occurs even with the addition of excess of NH4OH.This is because the concentration of OH– ions from the ionization of NH4OH is so
low that it cannot precipitate the hydroxide of calcium.
Question 7
Why is an alkali added drop by drop to the salt solution?
Answer 7
If an alkali is added too quickly, then it is easy to miss a precipitate which redissolves in excess alkali.
Question 8
Write balanced equations:
(a) Reaction of sodium hydroxide solution with iron (III) chloride solution.
(b) Copper sulphate solution with ammonium hydroxide solution.
Answer 8
(a)
(b)

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Excercise- 4 Analytical Chemistry Solutions ICSE Class-10

(Ammonium Hydroxide and Sodium Hydroxide)

Question 1
Write the probable colour of the following salts?
(a) Ferrous salts
(b) Ammonium salts
(c) Cupric salts
(d) Calcium salts
(e) Aluminium salts
Answer 1
(a) Ferrous salts: Light green
(b) Ammonium salts: Colourless
(c) Cupric salts: Blue
(d) Calcium salts: Colourless
(e) Aluminium salts: Colourless
Question 2
Name:
(a) a metallic hydroxide soluble in excess of NH4OH.
(b) a metallic oxide soluble in excess of caustic soda solution.
(c) a strong alkali.
(d) a weak alkali.
(e) Two colourless metal ions.
(f) Two coloured metal ions.
(g) a metal that evolves a gas which burns with a pop sound when boiled with alkali solutions.
(h) Two bases which are not alkalis but dissolve in strong alkalis.
(i) a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
(j) a colourless cation not a representative element.
Answer 2
(a) Cu(OH)2
(b) ZnO
(c) NaOH
(d) NH4OH
(e) Na+, Ca2+
(f) Fe2+, Mn2+
(g) Aluminium
(h) Zn(OH)2 and Al(OH)3
(i) PbO
(j) Ammonium ion
Question 3
Write balanced equations for Q.2 (g) and (i).
Answer 3

Question 4
What happens when ammonia solution is added first drop wise and then in excess to the following solutions:
(i) CuSO4(ii)ZnSO4(iii)FeCl3
Write balanced equations for these reactions.
Answer 4
(i)
(ii)

(iii)
Question 5
What do you observe when caustic soda solution is added to the following solution: first a little and
then in excess.
(a) FeCl3 ,
(b) ZnSO4,
(c) Pb(NO3)2 ,
(d) CuSO4?
Write balanced equations for these reactions.
Answer 5

Question 6
Name the chloride of a metal which is soluble in excess of ammonium hydroxide. Write equation for the same.
Answer 6
Zinc chloride (ZnCl2) is soluble in excess of ammonium hydroxide.
Question 7
On adding dilute ammonia solution to a colourless solution of a salt, a white gelatinous precipitate appears. This precipitate however dissolves on addition of excess of ammonia solution. Identify (choose from Na, Al, Zn, Pb, Fe)
(a) Which metal salt solution was used?
(b) What is the formula of the white gelatinous precipitate obtained?
Answer 7
(a) ZnCl2
(b) Zn(OH)2
Question 8
Name:
(a) A yellow monoxide that dissolves in hot and concentrated caustic alkali.
(b) A white, insoluble oxide that dissolves when fused with caustic soda or caustic potash.
(c) A compound containing zinc in the anion.
Answer 8
(a) PbO
(b) ZnO
(c) K2ZnO2
Question 9
Select the correct answers:
(a) Colour of an aqueous solution of copper sulphate is
(i) Green
(ii) Brown
(iii) Blue
(iv) Yellow
(b) Colour of the precipitate formed on adding NaOH solution to iron sulphate solution is
(i) White
(ii) Brown
(iii) Green
(iv) Pale blue
(c) A metal which produces hydrogen on reacting with alkali as well as with acid.
(i) Iron
(ii) Magnesium
(iii) Zinc
(iv) Copper
(d) The salt solution which does not react with ammonium hydroxide is
(a) Calcium nitrate
(b) Zinc nitrate
(c) Lead nitrate
(d) Copper nitrate
Answer 9
(a) (iii)
Aqueous solution of copper sulphate is blue.
(b) (iii)
FeSO4 + 2NaOH → Fe(OH)2 + Na2SO4
(Dirty green, (Colourless)
gelatinous ppt.)
(c) (iii)
Zn + 2NaOH → Na2ZnO2 + H2
Sodium zincate
(Colourless)
Zz Zn + HCl → ZnCl2 + H2
(d) Option (a)
The salt solution which does not react with ammonium hydroxide is calcium nitrate.
Question 10
What do you observe when freshly precipitated aluminum hydroxide reacts with caustic soda solution?Give balanced equation.
Answer 10
When freshly precipitated aluminum hydroxide reacts with caustic soda solution, whitesalt of sodium meta aluminate is obtained.
Question 11
You are provided with two reagent bottles marked A and B. One of which contains NH4OH solution and the other contains NaOH solution. How will you identify them by a chemical test?
Answer 11
Reagent bottles A and B can identified by using calcium salts such as Ca(NO3)2.
On adding NaOH to Ca (NO3)2, Ca (OH) 2 is precipitated as white precipitate which is sparingly soluble in excess of NaOH.
Ca(NO3)2+2NaOHCa(OH)2+2NaNO3
Whereas, on addition of NH4OH to calcium salts, no precipitation of Ca(OH)2 occurs even with addition of excess of NH4OH because the concentration of OH–ions from the ionization of NH4OH is so low that it cannot precipitate the hydroxide of calcium.
So the reagent bottle which gives white precipitate is NaOH and the other is NH4OH.
Question 12
Distinguish by adding: sodium hydroxide solution and ammonium hydroxide solution to
(a) Calcium salt solution and lead salt solution
(b) Lead nitrate solution and zinc nitrate solution
(c) Copper salt solution and ferrous salt solution
(d)Fe(II) salt solution and Fe(III) salt solution
(e) Ferrous nitrate and lead nitrate
Answer 12
(a) Sodium hydroxide on reaction with calcium salt gives a milky white precipitate, while that of with lead it gives chalky white precipitate.
(b) Sodium hydroxide and ammonium hydroxide on reaction with lead salt gives brown coloured precipitate, while that of with zinc it forms white gelatin like precipitate.
(c) Sodium hydroxide and ammonium hydroxide on reaction with Copper salt gives pale blue coloured precipitate, while that of with ferrous salt solution it forms dirty green coloured precipitate.
(d)Sodium hydroxide and ammonium hydroxide on reaction with Fe(II) salt gives dirty green coloured precipitate, while that of with Fe(III) salt solution it forms reddish brown insoluble precipitate.
(e) Ammonium hydroxide on reaction with lead nitrate gives a chalky white insoluble precipitate, while that of with ferrous nitrate will not give any precipitation.
Question 13
How will you distinguish lead carbonate and zinc carbonate in solution?
Answer 13
Lead carbonate is dissolved in dilute nitric acid and then ammonium hydroxide is added to it. A white precipitate is formed which is insoluble in excess.
Zinc carbonate is dissolved in dilute nitric acid and then ammonium hydroxide is added to it. A white precipitate is formed which is soluble in excess.
Question 14
What is observed when hot concentrated caustic soda solution is added to
(a) Zinc
(b) Aluminium
Write balanced equations.
Answer 14
(a) Zn + 2NaOH→ Na2ZnO2 + H2
(b) 2Al + 2NaOH + 2H2O→ 2Na2AlO2 + 3H2
Question 15
(a) What do you understand by amphoteric oxide?
(b) Give the balanced equations for the reaction with two different amphoteric oxides with a caustic alkali.
(c) Name the products formed.
Answer 15
(a) Amphoteric oxides are compounds which react with both acids and alkalis to form salt and water.
(b) ZnO+ 2NaOH → Na2ZnO2 + H2O
Al2O3 + 2NaOH → 2NaAlO2 + H2O
(c) Sodium zincate
Aluminium zincate
Question 16
Write the balanced equations for the following conversions:
"

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                                                                     Class - X BIOLOGY

D. Long answer type
1.Due to the shortage of water the leaves droop down and loose their turgidity.This flaccid condition of leaves is called wilting. Some plants show wilting of their leaves at noon even when the soil is well watered because the rate of transpiration at that time is higher than the rate of absorption of water by the roots.

2.The stomata in most plants are more numerous on the lower surface of a leaf instead of being on the upper surface because lower surface is less exposed to sunlight as compared to upper surface.

3. Cover a potted rose plant.With a transparent polythene bag tied its mouth around the base of the stem of the plant in sunlight for an hour or two.Drops of water will soon appear on the inner side of the bag due to saturation of water vapour given out by the leaves.A similar empty polythene bag with its mouth tied and kept in sunlight will show no drops of water.This is a control to show that plants transpire water. Therefore this experiment demonstrate transpiration in rose plant.(Diagram is on page no.55,fig.5.1)

4. Photometer is a device which measures the rate of water intake by a plant,and this water intake is almost equal to the water lost through transpiration.

5.Lenticular transpiration is the transpiration which occurs through lenticels which are present on the old green stems of the plant. These are the minute openings which remain open all the time.
LENTICULAR TRANSPIRATION
a.It occurs through lenticels.
b. The amount of lenticular transpiration is very small.
STOMATAL TRANSPIRATION
a.It occurs through stomata.
b.the amount of stomatal transpiration is very large.

6.(a)The intensity of sunlight
(b) temperature
(c) velocity of wind

7.The huge quantities of water released into the atmosphere by stretches of fields and particularly forests through transpiration, which increases the moisture in the atmosphere and brings rain.

8.No,these are not the dew drops.These drops are actually the water drops which are coming out from the margins of the leaves in humid conditions due to the less rate of transpiration and excess amount of water present in the plant body.

9.(a)The rate of transpiration is directly affected by intensity of light.If the intensity of light is more the rate of transpiration will be more,if the intensity of light is less the rate of transpiration will be less.

(b)The rate of transpiration is inversely proportional to humidity.If the humidity is high the rate of transpiration will be less and if the humidity is less in the atmosphere, then the transpiration will be more.

E. Structured/Application Skill Type

1.(i) left uncoated because in this leaf transpiration occurs from both surfaces so it will be the most limp.
(ii) coated on both surfacesbecause both the sides of the leaf is covered by Vaseline so it shows least limping.

2(a) Transpiration
(b)To prevent evaporation from the surface of water.
(c)To measure the amount of lost water during transpiration.
(d) yes more rate of transpiration will be their. Inshot more loss of weight of plant.
3.(a) Ganong's photometer
Transpiration
Exercise A multiple choice type
Solutions
1(a) open stomata, dry atmosphere and moist soil
2(a) increase
3(d) atmosphere is dry and temperature is high
4(c) sunken stomata
5(d) hydathodes
6(d) transpiration
7(d) hot,dry and windy
8(a) stomata
9(c) loss of water, as water vapour, by a plant.

Exercise B
Very short answer type
1 Name the following:
(a) lenticels
(b) guttation
(c) potometer
(d) nerium
(e) ganong's potometer
(f) cuticle, stomata
(g) hydathodes
(h) guttation

2 fill in the blanks:
(a) vapour, aerial
(b) stomata, transpiration
(c) suction, water

C short answer type
1 functional activity
(a) hydathodes and guttation
(b) leaf spines and reduced transpiration
(c) lenticels and lenticular transpiration/diffusion of gases
(d) xylem and conduction of water

2(a)true or false
(1) false
Most transpiration occurs at midday
(2) true
(3) true
(4) false
Potometer is an instrument used for measuring the rate of transpiration in green plants.

3 Give suitable explanation for the following:
(a) Higher rate of transpiration is recorded on a windy day rather than on a calm day because transpiration increases with the velocity of wind. If the wind blows faster,the water vapour released during transpiration is removed faster and the area outside the leaf does not get saturated with water vapour.

(b) Excessive transpiration results in the wilting of leaves because the rate of transpiration exceeds the rate of absorption of water by the roots. Hence the cells lose turgidity.

(c) Out of total water absorbed by plants only a small quantity of this water is used by the plant in photosynthesis and other activities.The rest of it is almost lost to the atmosphere as water vapour as a result of transpiration. So, water transpired is the water absorbed.

(d) More transpiration occurs from the lower surface of a dorsiventral leaf because in a dorsiventral leaf more stomata are present on the lower surface as compared to upper surface.

(e) Cork and bark are made up of flattened dead cells with fatty substance which is impermeable to water and gases and thereby, help in preventing loss of water.

(f) Transpiration is a process in which water evaporates from a plant specially through the stomata of the leaves.In this way transpiration helps to low down the temperature of the plant in hot weather.When the body temperature rises sweat glands excrete small amount of water along with urea and salts to the surface of skin and it also cools the body by evaporation.So in this way perspiration and transpiration helps to cool the body temperature of the organism.

(g)On a bright sunny day the leaves of certain plants roll up because the rate of transpiration exceeds the rate of absorption of water by roots.

4 true or false
(a) true
Because potometer is attached by a leaf shoot which contains numerous stomata.
(b) true
Because both are the pores on plant body through which transpiration occurs.
(c) false
Because if humidity is high then transpiration is less and vice versa.
(d) true
Because it is an adaptation of plant to reduce transpiration.
(e) true
Because at that time the intensity of sunlight is more which favours transpiration.

5 Differentiate between guttation and bleeding
GUTTATION
1 It is a loss of water as droplets along the margins of leaves.
2 It occurs through hydathodes found at the end of veins.
BLEEDING
1 It is the direct flowing out of plant sap.
2 It occurs from the ruptured or cut surfaces of a plant.

Class - x    English language

Total English -10

Chapter -1 is solved in the book
Chapter-2
Q.5 (a)1.was affected

2.made
3.fermented
4.became
5.working
6.converts
7.turns
8.packs
b) 1.up
2.of
3.away
4.in
5.into
6.over
7.after
8.for

c)1. The examination had begun before we reached the hall.
2.I don't care whether Manav join me or not.
3. As it is very cold,we can't wear cotton clothes.
4.Since you helped him ,he will be grateful to you.

d)1.Hardly had the train arrived when all rushed into the compartments.
2.There was a collision between a bus and a car.
3.How long can I bear it?
4.You cannot come with us for the picnic unless your father permits you.
5.We had never met each other since 2009.
6.The Commander ordered the soldiers not to give up and march on.
7.Put your tools away lest people should fall over them.
8.I wish I had been appointed to the post.
Chapter-3
Q.5.
a)1.doubled
2.shows
3.generated
4.was processed

5.compared
6.worst
7.collected
8.treated
b) 1.by
2.into
3.with
4.away
5.about
6.up
7.away
8.towards
c)1.As it was very hot I could not go out.
2.The room is too small to accommodate all of us.
3.The book that I borrowed from my neighbour is good.
4.Aditi was too terrified to speak

d)1. I suggested to my sister that we should go to the market the next day for shopping.
2.As he is poor,he cannot afford such expensive treatment.
3. Inspite of being rich man, he is not proud.
4.Bina inherited a big fortune from her father.
5.He pleaded for his ignorance of law.
6.It is believed that he was involved in the crime.
7.I wish I had taken my doctor's advice.
8.He not only passed the examination well but also won the first prize.

                                                                                           Chapter-4

Q.5 a)1.wants
2.disposal
3.adopted
4.mandated
5.will give
6.bringing
7.stopped
8.have seen that

b) 1. Under
2.down
3.after
4.over
5.on
6.up
7.for
8.without

c)1. Ankita as well as Kalyani is pretty.
2.Everybody knows that the shopkeeper is cunning.
3.I do not know why he is not coming to school.
4.He is poor however not a cheat.

d)1.Tagore was one of the most famous artists.
2.Unless you tell the truth ,you will be punished.
3.He asked if he might have a cup of milk.
4.If he is given some more time,he will complete this work by tomorrow.
5.We organised a function so that we may raise funds for the school.
6.Who has not heard of the Quit India Movement?
7.I prefer small towns to big cities.
8.Inspite of being too young she was appointed by them.
Chapter-5
Q.5 a)1.to control
2.published
3.shows
4. cools
5.are created
6.aid
7.understanding
8.help
b)
1.on
2.by
3.aside/away
4.forth
5.through
6.on
7.up
8.under
c)1.I would not have completed the task but for Anu's help.
2.Mr Khosla cannot be late as he is punctual.
3.Kindly tell me why you did not complete your project.
4.We will wait for you till you come back.

d)1.The police not only kept a watch on his movements but also tapped his phones.
2.Everyone will admit that she is honest.
3.If you had not helped me I would not have succeeded.
4.He spent his whole life here since his birth.
5.The principal said,"I will look into the case."
6.Inspite of knowing him for long,I have not developed respect for him
7.John did not understand why Anita was annoyed with him.
8.Tom can run faster than anybody else in our team.

Class X Chemistry

Chapter 1 - Periodic Table, Periodic Properties and Variations of Properties Exercise Ex. 1

Question 1

Name an

(a) An alkali metal in period 3 and halogen in period 2

(b) The noble gas with 3 shells

(d) The element of period 3 with valency 4.

(e) The element in period 3 which does not form an oxide.

(f) The element of lower nuclear charge out of Be and Mg.

(g) Which has higher E.A. Fluorine or Neon?

(h) Which has maximum metallic character Na, Li or K?

Solution 1

(a) Na and F

(b) Argon

(d) Silicon

(e) Argon

(f) Be

(g) Fluorine

(h) K

Question 2

Choose the most appropriate answer from [SO₂, SiO₂, Al₂O₃, CO, MgO, Na₂O]

a. A covalent oxide of a metalloid.

b. An oxide which when dissolved in water forms acid.

c. A basic oxide.

d. An amphoteric oxide.

Solution 2

a. A covalent oxide of a metalloid. - SiO₂ (Si is a metalloid)

b. An oxide which when dissolved in water forms acid. - SO₂ (SO₂ + H₂O → H₂SO₃)

c. A basic oxide. - Na₂O (Na₂O + H₂O → 2NaOH)

d. An amphoteric oxide. - Al₂O₃ (shows both acidic and basic properties)

Question 3

Arrange the following as per instructions given in the brackets.

a. Mg, Cl, Na, S, Si (decreasing order of atomic size)

b. Cs, Na, Li, K, Rb (increasing metallic character)

c. Na, K, Cl, S, Si (increasing ionisation potential)

d. Cl, F, Br, I (increasing electron affinity)

e. Cs, Na, Li, K, Rb (decreasing electronegativity)

Solution 3

a. Mg, Cl, Na, S, Si (decreasing order of atomic size) -

Na >mg>si>s>cl

b. Cs, Na, Li, K, Rb (increasing metallic character)

Li < Na < K < Rb < Cs

c. Na, K, Cl, S, Si (increasing ionisation potential) -

Cl > S > Si > Na > K or K<na<si<s<cl

1256 > 999 >786 > 496 > 419

d. Cl, F, Br, I (increasing electron affinity) -

I < Br < F < Cl

-295 KJ mol^-1 < -324 KJ mol^-1 < -327.9 KJ mol^-1 < -349 KJ mol^-1

e. Cs, Na, Li, K, Rb (decreasing electronegativity) -

Li > Na > K = Rb > Cs

1.0 > 0.9 > 0.8 = 0.8 > 0.7

Question 4

Chorine in the periodic table is surrounded by the elements with atomic number 9, 16, 18 and 35.

(a) Which of these have physical and chemical properties resembling chlorine?

(b) Which is more electronegative than chlorine?

Solution 4

(a) An element with atomic number 9 and 35

(b) An element with atomic number 9.

Question 5

First Ionization enthalpy of two elements X and Y are 500 kJ/mol^-1 and 375 kJ /mol^-1 respectively. Comment about their relative position in a group as well in a period.

Solution 5

The ionisation energy is the minimum energy required to remove the outermost electron from a gaseous neutral atom to form a cation.

Position in a group: X will be above Y ( because of ionisation energy decreases down the group )

Position in a period: X will be the right side of Y ( because ionisation energy increases from left to right)

Question 6

Arrange the following in order of increasing radii:

(a) Cl¯, Cl

(b) Mg²⁺, Mg, Mg⁺

Solution 6

(a) Cl < Cl¯

(b) Mg²⁺ < Mg⁺ < Mg

Question 7

Which element from the following has the highest ionization energy?

(a) P, Na, Cl

(b) F, O, Ne

Explain your choice.

Solution 7

(a) Cl

Metals have low ionisation energy and non-metals have high ionisation energy. Also, across the period, ionisation energy tends to increase. The elements P, Na and Cl belong to the third period. Na - Group 1, P - Group 15 and Cl - Group 17.

(b) Ne

Inert gases have zero electron affinity because of their stable electronic configuration.

Ionisation energy decreases with an increase in the atomic size, i.e. it decreases as one moves down a group. Ne, He and Ar are inert gases. He - Period 1, Ne - Period 2 and Ar - Period 3.

Question 8

The electronegativities(according to Pauling) of the elements in period 3 of the periodic table are as follows with elements arranged in alphabetical order:

Al	Cl	Mg	Na	P	S	Si
1.5	3	1.2	0.9	2.1	2.5	1.8

Arrange the elements in the order in which they occur in the periodic table from left to right.

(The group 1 element first, followed by the group 2 element and so on, up to group 7).

Solution 8

Na, Mg, Al, Si, P, S, Cl

Question 9

Choose the word or phrase from the brackets which correctly completes each of the following statements:

a. The element below sodium in the same group would be expected to have a ............... (lower/higher) electro-negativity than sodium, and the element above chlorine would be expected to have a (lower/higher) ionisation potential than chlorine.

b. On moving from left to right in a given period, the number of shells ................. (remains the same/increases decreases).

c. On moving down a group, the number of valence electrons .................. (remains the same/increases/decreases).

d. Metals are good ................. (oxidising agents/reducing agents) because they are electron ............. (acceptors/donors).

Solution 9

(a) The element below sodium in the same group would be expected to have a lower electro-negativity than sodium, and the element above chlorine would be expected to have a higher ionisation potential than chlorine.

(b) On moving from left to right in a given period, the number of shells remains the same.

(d) Metals are good reducing agents because they are electron donors.

Question 10

Parts (a) to (e) refer to change in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the correct answer.

(a) The non-metallic character of the elements:

(i) Decreases

(ii) Increases

(iii) Remains the same

(iv) Depends on the period

(b) The electronegativity:

(i) Depends on the number of valence electrons

(ii) Remains the same

(iii) Decreases

(iv) Increases

(i) goes up and down

(ii) Decreases

(iii) Increases

(iv) Remains the same

(d) The atomic size:

(i) Decreases

(ii) Increases

(iii) Remains the same

(iv) Sometimes increases and sometimes decreases

(e) The electron affinity of elements in group 1 to 7 :

(i) Goes up and then down

(ii) Decreases and then increases

(iii) Increases

(iv) Decreases

Solution 10

(a) Increases

(b) Increases

(d) Decreases

(e) Increases

Question 11

The elements of one short period of the periodic table are given below in order from left to right:

Li Be B C O F Ne

(a) To which period do these elements belong?

(b) One element of this period is missing. Which is the missing element and where should it be placed?

(d) Which one of the above element belongs to the halogen series?

Solution 11

(a) Period 2

(b) Nitrogen (N), between carbon and oxygen

(d) Fluorine

Question 12

Select the correct answer from the choices A, B, C, D which are given. Write down only the letter corresponding to correct answer.

With reference to the variation of properties in the Periodic table, which of the following is generally true?

A Atomic size increases from left to right across a period.

B Ionization potential increases from left to right across a period.

C Electron affinity increases going down a group.

D Electro-negativity increases going down a group.

Solution 12

Question 13

Among Period 2 elements A, B, C and D, the one which has high electron affinity is

A. Lithium

B. Carbon

C. Fluorine

D. Neon

Solution 13

Correct option is A. Lithium

In a period from left to right, electron affinity decreases as the non-metallic character increases.

Question 14

Group No.'s

IA	IIA	IIIA	IVA	VA	VIA	VIIA	0
1	2	13	14	15	16	17	18
Li		D			O	J	Ne
A	Mg	E	Si		H	K
B	C		F	G			L

Select from the table:

i. Which is the most electronegative?

ii. How many valence electrons are present in G?

iii. Write the formula of the compound between B and H.

iv. In the compound between F and J, what type of bond will be formed?

v. Draw the electron dot structure for the compound formed between C and K.

Solution 14

i. The most electronegative is J.

ii. Valence electrons present in G are 5.

iii. B contains 1 valence electron and H contains 6 valence electrons. So, the valency of B is +1 and the valency of H is - 2.

iv. In the compound between F and J, the type of bond formed will be covalent.

v. The electron dot structure for the compound formed between C and K is

Selina Solutions Icse Class 10 Chemistry Chapter - Periodic Table Periodic Properties And Variations Of Properties

Question 15

The number of electrons in the valence shell of a halogen is ………. A - 1, B - 3, C - 5, D - 7.

Solution 15

The number of electrons in the valence shell of a halogen is 7.

Correct option: D

Question 16

Electronegativity across the period ............ [increases/decreases].

Solution 16

Electronegativity across the period increases.

Question 17

Non-metallic character down the group ………… [increases/decreases].

Solution 17

Non-metallic character down the group decreases.

Question 18

Atomic number of an element is 16. State

i. to which period it belongs

ii. the number of valence electrons in the element

iii. is the element metal or non-metal

Solution 18

Atomic number of an element is 16.

1. It belongs to Period 3.

2. The number of valence electrons in the element is 6.

3. The element is a non-metal.

Question 19

Give reasons - The oxidising power of elements increases from left to right along a period.

Solution 19

The oxidising power of elements depends on the tendency to gain electrons which increases from left to right along a period due to increase in nuclear pull.

Question 20

Select the correct answer:

i. Across a period, the ionisation potential ………… [increases, decreases, remains same]

ii. Down the group, electron affinity ………… [increases, decreases, remains same]

Solution 20

i. Across a period, the ionisation potential increases.

ii. Down the group, electron affinity decreases.

Question 21

Choose the correct answer from the choice given:

In the periodic table, alkali metals are placed in the group A : 1, B : 11, C : 17, D : 18.

Solution 21

In the periodic table, alkali metals are placed in Group I. So, the correct option is A.

Question 22

Choose the correct answer from the choice given:

Which of the following properties do not match with elements of the halogen family?

A. They have seven electrons in their valence shell.

B. They are highly reactive chemically.

C. They are metallic in nature.

D. They are diatomic in their molecular form.

Solution 22

The correct option is C.

The elements of halogen family are non-metallic in nature.

Question 23

State the group and period of the element having three shells with three electrons in the valence shell.

Solution 23

Three shells indicate that the element belongs to the third period.

Three valence electrons indicate that the element belongs to the third group.

Question 24

Choose the correct answer from the option:

An element in Period 3 whose electronic affinity is zero.

A. Neon

B. Sulphur

C. Sodium

D. Argon

Solution 24

Correct option: (D) Argon

Question 25

Give reason:

i. Ionisation potential of the element increases across a period.

ii. Alkali metals are good reducing agents.

Solution 25

i. Because the atomic radius decreases across a period. Due to this, attraction between the nucleus and the electron increases. This results in an increase in the ionisation potential.

ii. Alkali metals are good reducing agents because they have a greater tendency to lose electrons.

Question 26

There are three elements E, F, G with atomic numbers 19, 8 and 17 respectively.

Classify the above elements as metals and non-metals.

Solution 26

Electronic configuration of E with atomic number 19 = 2,8,8,1

E is a metal.

Electronic configuration of F with atomic number 8 =

2,6

F is a non-metal.

Electronic configuration of G with atomic number 17 =

2,8,7

G is a non-metal.

Question 27

Name: A metal present in Period 3, Group I of the periodic table.

Solution 27

A metal present in Period 3, Group I of the periodic table is sodium.

Question 28

Among the Period 2 elements, the element which has high electron affinity is

A. Lithium

B. Carbon

C. Chlorine

D. Fluorine

Solution 28

Correct option: (D) Fluorine

Question 29

Identify: The element which has the highest ionisation potential.

Solution 29

The element which has the highest ionisation potential is helium (He).

Question 30

Group No.	1-1A	2-IIA	13-IIIA	14-IVA	15-VA	16-VIA	17-VIIA	18-0
2^nd period	Li		D			O	J	Ne
3^rd period	A	Mg	E	Si		H	M
4^th period	R	T	I		Q	U		Y

In the above table, H does not represent hydrogen. Some elements are given in their own symbol and position in the periodic table while others are shown with a letter. Answer the following questions.

i. Identify the most electronegative element.

ii. Identify the most reactive element of Group I.

iii. Identify the element from Period 3 with least atomic size.

iv. How many valence electrons are present in Q?

v. Which element from group 2 would have the least ionisation energy?

vi. Identify the noble gas of the fourth period.

vii. In the compound between A and H, what type of bond would be formed and give its molecular formula.

Solution 30

i. I

ii. R

iii. M

iv. 5

v. T

vi. Y

vii. Ionic bond will be formed and the molecular formula is A₂H.

Question 31

Choose the correct answer from the choice given:

i. Ionisation potential increases over a period from left to right because the

A. Atomic radius and nuclear charge increase

B. Atomic radius and nuclear charge decrease

C. Atomic radius increases and nuclear charge decreases

D. Atomic radius decreases and nuclear charge increases

ii. An element A belonging to Period 3 and Group II will have

A. 3 shells and 2 valence electrons

B. 2 shells and 3 valence electrons

C. 3 shells and 3 valence electrons

D. 2 shells and 2 valence electrons

Solution 31

i. Correct option: D (atomic radius decreases and nuclear charge increases)

ii. Correct option: A (3 shells and 2 valence electrons)

Question 32

(b) An atomic number of an element Z is 16. Answer the following:

i. State the period and group to which Z belongs.

ii. Is Z a metal or a non-metal?

Solution 32

(a) An element Z having atomic number 16 is Sulphur.

(i) Sulphur belongs to Period 3 and Group 16.
(ii) Sulphur is a non-metal.

Question 33

State the formula of the compound between Z and hydrogen.

Solution 33

Two hydrogen atoms combine with one sulphur atom to form hydrogen sulphide (H₂S) gas.

Question 34

M is a metal above hydrogen in the activity series and its oxide has the formula M₂O. This oxide, when dissolved in water, forms the corresponding hydroxide which is a good conductor of electricity. In the above context, answer the following:

i. What kind of combination exists between M and O?

ii. State the number of electrons in the outermost shell of M.

iii. Name the group to which M belongs.

Solution 34

i. Ionic bond exists between M and O.

ii. 1 electron is present in the outermost shell of M.

iii. M belongs to Group 1 in the modern periodic table.

Question 35

Give one word or phrase for: The amount of energy released when an atom in the gaseous state accepts an electron to form an anion.

Solution 35

Electron affinity

Question 36

Match the option A and B with the statements (i) and (ii):

A. metal	(i) The metal that forms two types of ions
B. iron	(ii) An element with electronic configuration 2, 8, 8, 3

Solution 36

A: (ii)

B: (i)

Question 37

Among the elements given below, the element with the least electronegativity is

(i) Lithium

(ii) Carbon

(iii) Boron

(iv) Fluorine

Solution 37

(i) Lithium

Reason: Electronegativity increases from left to right. Lithium is present on the left side of the periodic table; hence, it will be the least electronegative element.

Question 38

The metals of Group 2 from top to bottom are Be, Mg, Ca, Sr and Ba.

(i) Which of these elements will form ions most readily and why?

(ii) State the common feature in the electronic configuration of all these elements.

Solution 38

(i) Ba metal will form ions readily because the ionisationenergy decreases down the group as the size increases.

(ii) On moving down the group, the number of electrons in the outermost shell, i.e.valence electrons remain the same. So, the valency in a group remains the same, i.e. 2.

Question 39

Metals are good _____________ (oxidising agents/reducing agents) because they are electron __________ (acceptors/donors).

Solution 39

Metals are good reducing agents because they are electron donors.

Question 40

An element with the atomic number 19 will most likely combine chemically with the element whose atomic number is :

A. 17

B. 11

C. 18

D. 20

Solution 40

(A) 17

Element with atomic number 19 will lose 1 electron (to achieve the noble gas configuration) which can be accepted by the element with atomic number 17.

Question 41

Rewrite the following sentences by using the correct symbol > (greater than) or < (less than) in the blanks given :

1. The ionization potential of potassium is _________________ that of sodium.

2. The electronegativity of lodine is ___________ that of Chlorine.

Solution 41

1. less than

2. less than

Question 42

Fill in the blanks by selecting the correct word from the brackets :

i. If an element has a low ionization energy then it is likely to be ______________ (metallic / non-metallic).

ii. If an element has seven electrons in its outermost shell then it is likely to have the ______________ (largest / smallest) atomic size among all the elements in the same period.

Solution 42

i. Metallic

ii. Smallest

Question 43

In Period 3 of the Periodic table, element B is placed to the left of element A. On the basis of this information, choose the correct word from the brackets to complete the following statements:

i. The element B would have (lower /higher) metallic character than A.

ii. The element A would probably have (lesser / higher) electron affinity than B.

iii. The element A would have (greater /smaller) atomic size than B.

Solution 43

i. The element B would have higher metallic character than A.

ii. The element A would probably have higher electron affinity than B.

iii. The element A would have smaller atomic size than B.

Chapter 1 - Periodic Table, Periodic Properties and Variations of Properties Exercise Intext 1

Question 1

(i) State modern periodic law.

(ii) Name the scientist who stated the law.

(iii) How many groups and periods does modern periodic table have?

Solution 1

(i) The modern periodic law states that "The properties of elements are the periodic functions of their atomic number."

(ii) Henry Moseley put forward the modern periodic law.

(iii) Modern Periodic table has 7 periods and 18 groups.

Q2 elements of group 1and elements of gp 17both have valency I1 ? explain

Ans because they have one electron in their outermost shell to lose to gain e^-

Question 3

What are horizontal rows and vertical columns in a periodic table known as?

Solution 3

The horizontal rows are known as periods and vertical columns in theperiodic table are known as groups.

Question 4

Periodicity is observed due to the similar.............

(number of valence electrons/ atomic number/ electronic configuration)

Solution 4

Periodicity is observed due to the similar electronic configuration.

Question 5

How does electronic configuration in atoms change

(i) In a period from left to right?

(ii) In a group top to bottom?

Solution 5

(i) Though the number of shells remain the same, number of valence electrons increases by one, as we move across any given period from left to right.

(ii) While going from top to bottom in a group, the number of shells increases successively i.e. one by one but the number of valence electrons remains the same.

Question 6

Correct the statements.

(i) Elements in the same period have equal valency.

(ii) Valency depends upon the number of shells in an atom.

(iii) Copper and zinc are representative elements.

(iv) Transition elements are placed at the extreme right of the periodic table.

Solution 6

(i) Elements in the same group have equal valency.

(ii) Valency depends upon the number of valence electrons in an atom.

(iii) Copper and zinc are transition elements.

(iv) Noble gases are placed at the extreme right of the periodic table.

Question 7

Name 2 elements in each case:

(i) Alkali metals

(ii) Alkaline earth metals

(iii) Halogens

(iv) Inert gas

(v) Transition metals

(vi) Lanthanides

(vii) Actinides

Solution 7

(i) Sodium and Potassium

(ii) Calcium and Magnesium

(iii) Chlorine and Bromine

(iv) Neon and Argon

(v) Iron and Cobalt

(vi) Cerium and Europium

(vii) Uranium and Neptunium

Question 8

What do you understand by?

(i) Periodicity

(ii) Typical elements

(iii) Orbits

Solution 8

(i) The properties that reappear at regular intervals, or in which there is a gradual variation at regular intervals, are called periodic properties and the phenomenon is known as the periodicity of elements.

(ii) The third-period elements, Na, Mg, Al, Si, P and Cl summarize the properties of their respective groups and are called typical elements.

(iii) Elements revolve around the nucleus in certain definite circular paths called orbits or shells.

Question 9

Name 2 elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?

Solution 9

Beryllium and magnesium will show similar chemical reactions as calcium. Since these elements belong to same group 2 andalso have two electrons in their outermost shell like calcium.

Question 10

Name the (i) metals, (ii) metalloids and (iii) non-metals in the first twenty elements.

Solution 10

i. Metals: Lithium, Beryllium, Sodium, Magnesium, Aluminium, Potassium, Calcium

ii. Metalloids: Boron, Silicon

iii. Non-metals: Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Phosphorous, Sulphur, Chlorine, Argon

Question 11

Fluorine, Chlorine and Bromine are put in one group on the basis of their similar properties.

i. What are those similar properties?

ii. What is the common name of this group or family?

Solution 11

(i) Properties: Non-metallic, highest electronegativity in the respective periods, highest ionisation potentials in the respective periods, highest electron affinity in the respective periods

(ii) Salt-forming; hence, the common name is halogens.

Question 12

What is the main characteristic of the last element in each period of the Periodic Table? What is the general name of such elements?

Solution 12

The main characteristic of the last element in each period of the periodic table is they are inert or chemically unreactive.

The general name of such elements is 'Noble gases'.

Question 13

According to atomic structure, what determines which element will be the first and which will be the last in a period?

Solution 13

According to atomic structure, the number of valence electrons determines the first and the last element in a period.

Question 14

How does the number of :

i. Valence electrons and

ii. Valency vary on moving from left to right in the third period of the periodic table?

Solution 14

i. The valence electrons increase from 1 to 8 in the 3rd period of the periodic table.

ii. On moving from left to right, the valency increases from 1 to 4 and then decreases from 4 to 0.

Question 15

Name the type of elements, which have their

(i)Outermost shell complete

(ii)Outermost shell incomplete

(iii) Two outermost shells incomplete

(iv)One electron short of octet

(v) Two electrons in the outermost orbit.

Solution 15

(i) Noble gases

(ii) Representative elements

(iii) Transition elements

(iv) Halogens

(v) Alkaline Earth metals

Question 16

An element has 2 electrons in its N shell

(i) What is its atomic number?

(ii) State its position in periodic table

(iii) Is it metal or non-metal?

(iv) State the name assigned to this group.

Solution 16

(i) 30

(ii) It belongs to group 12 and fourth period.

(iii) It is a metal.

(iv) The name assigned to this group is IIB.

Question 17

Answer the following in respect of element ³²₁₆S.

(i)Give its electronic configuration.

(ii)To which group and period does it belong?

(iii)What is its valency?

(iv)Is it metal or non-metal?

(v)Is it a reducing agent or oxidizing agent?

(vi)Give its formula with chlorine.

Solution 17

(i) Electronic configuration of S: 2,8,6

(ii) 16^th Group and 3^rd Period.

(iii) Valency of S = 8 - 6 = 2

(iv) Sulphur is a non-metal.

(v) It is an oxidizing agent.

(vi) Formula with chlorine = SC

Periodic Table, Periodic Properties and Variations of Properties Exercise Intext 2

Chapter 1

Question 1

What do you understand by atomic size? State its unit.

Solution 1

Atomic size is the distance between the centre of the nucleus of an atom and its outermost shell.

It's measured in Angstrom and Picometre.

Question 2

Give the trends in atomic size on moving

(i) Down the group

(ii) Across the period left to right.

Solution 2

(i) The atomic size of an atom increases when we go down a group from top to bottom.

(ii) It decreases as we move from left to right in a period.

Question 3

Arrange the elements of second and third period in increasing order of their atomic size.

Solution 3

Second Period: Fluorine < Neon < Oxygen < Nitrogen < Carbon < Boron < Beryllium < Lithium.

Third Period: Chlorine < Argon < Sulphur < Phosphorus < Silicon < Aluminum < Magnesium < Sodium.

Question 4

Why is the size of

(i) Neon greater than fluorine

(ii) Sodium is greater than magnesium.

Solution 4

(i) The size of Neon is bigger compared to fluorine because the outer shell of neon is complete(octet).As a result, the effect of nuclear pull over the valence shell electrons cannot be seen. Hence the size of Neon is greater than fluorine.

(ii) Since atomic number of magnesium is more than sodium but the numbers of shells are same, the nuclear pull is more in case of Mg atom. Hence its size is smaller than sodium.

Question 5

Which is greater in size

(i) An atom or a cation?

(ii) An atom or an anion?

(iii) Fe ²⁺or Fe³⁺?

Solution 5

(i) An atom is always bigger than cation since cation is formed by the loss of electrons; hence protons are more than electrons in a cation. So the electrons are strongly attracted by the nucleus and are pulled inward.

(ii) An anion is bigger than an atom since it is formed by gain of electrons and so the number of electrons are more than protons. The effective positive charge in the nucleus is less, so less inward pull is experienced. Hence the size expands.

(iii) Fe ²⁺ is bigger than Fe³⁺since Fe ²⁺ has more number of electrons than Fe³⁺and hence the inner pull by nucleus is less strong on it as compared to the pull on Fe³⁺.

Question 6

Arrange :

i. Be, Li, C, B, N, O, F (in increasing metallic character)

ii. Si, Na, Al, Mg, Cl, P, S (in decreasing non-metallic character)

Solution 6

i. In increasing metallic character: F < O < N < C < B < Be < Li

ii. In decreasing non-metallic character: Cl > S > P > Si > Al > Mg > Na

Question 7

State the trends in chemical reactivity:

(i) Across the period left to right

(ii) Down the group

Solution 7

(i) Across a period, the chemical reactivity of elements first decreases and then increases.

(ii) Down the group, chemical reactivity increases as the tendency to lose electrons increases down the group.

Question 8

A metal M forms an oxide having the formula M₂O₃. It belongs to the third period. Write the atomic number and valency of the metal.

Solution 8

Given: The metal belongs to the third period; there are three shells.

The chemical formula of the compound suggests that the valency of the metal is +3.

That means the valence electrons are 3; hence, it belongs to the third group.

Thus, the element must have the electronic configuration 2, 8, 3.

That means the total number of electrons is 13.

Valency = 3, Atomic number = 13

Question 9

An element X belong to 3rd period and 17^th group, state

(i) no of valence electrons in it.

(ii) name of the element.

(iii) name the family to which it belongs.

(iv) write the formula of the compound formed when it reacts with .

Solution 9

(i) The element from the 17^th group has 7 electrons in its outermost shell.

(ii) The name of the element is chlorine.

(iii) Chlorine belongs to the halogen family.

(iv) The element has three electrons in its outermost shell which it can donate; hence, its valency is three. While the valency of chlorine is 1. Thus, which is Aluminium can donate three electrons, and chlorine can accept 1 electron to get the stable electronic configuration.

Therefore, the formula of the compound is AlCl₃ or xy₃

Question 10

The given table shows elements with same number of electrons in its valence shell.

Elements	A	B	C
m.p	63.0	180.0	97.0

State :

(i) Whether these elements belong to same group or period.

(ii) Arrange them in order of increasing metallic character.

Solution 10

(i) Yes, these elements belong to the same group but are not from the same period.

(ii) We know that m.p. decreases on going down the group. Hence, from the above table, the elements can be ordered according to their period as follows:

Elements	B	C	A A
m.p.	180.0	97.0	63.0

The metallic character increases as one moves down the group.

Hence, the order of the given elements with increasing metallic character is as follows:

B<c<a

Question 11

Which one of the following has the largest atomic radius?

i. Sodium

ii. Potassium

iii. Magnesium

iv. Aluminium

Solution 11

Correct option: (ii) Potassium

Question 12

Which one has the largest size?

i. Br

ii. I

iii. I^-

iv. Cl

Solution 12

Correct option: (iii) I^-

Question 13

The metals of group 2 from top to bottom are Be, Mg, Ca, Sr and Ba.

i. Which one of these elements will form ions most readily and why?

ii. State the common feature in their electronic configuration.

Solution 13

(i) Barium will form ions most readily as the outermost valence electron which experiences the least force of attraction by positively charged nucleus can be given away readily to form cations.

(ii)All Group II elements have two valence electrons.

Question 14

Solution 14

Protons = 19, Neutrons = 39 - 19 = 20

Electronic configuration = 1s²2s²2p⁶3s²3p⁶4s¹ or2,8,8,1

Position in the periodic table = Group 1, Period 4

Protons = 15, Neutrons = 31 - 15 =16

Electronic configuration = 1s² 2s² 2p⁶ 3s² 3p³ or 2,8,5

Position in the periodic table = Group 3, Period 3

Question 15

The electronic configuration of an element T is 2, 8, 8, 1.

i. What is the group number of T?

ii. What is the period number of T?

iii. How many valence electrons are there in an atom of T?

iv. What is the valency of T?

v. Is it a metal or a non-metal?

Solution 15

i. Group = 1

ii. Period = 4

iii. Valence electrons = 1

iv. Valency = 1

v. Metal

Question 16

The element barium has atomic number 56. Look up its position in the periodic table and answer the following questions:

(i) Is it a metal or a non-metal?

(ii) Is it more or less reactive than calcium?

(iii) What is its valency?

(iv) What will be the formula of its phosphate?

(v) Is it larger or smaller than caesium (Cs) in size?

Solution 16

(i) It belongs to group II and has 2 valence electrons, so it is a metal.

(ii) Barium is placed below calcium in the group. Since the reactivity increases below the group, barium is more reactive than calcium.

(iii) It needs to lose 2 valence electrons to complete its octet configuration, so its valency is 2.

(iv) The formula of its phosphate will be Ba₃(PO₄)2.

(v) As we move from left to right in a period, the size decreases, so it will be smaller than caesium.

Question 17

In group I of the periodic table, three elements X,Y and Z have ionic radii 1.33 , 0.95 and 0.60 , respectively. Giving a reason, arrange them in the order of increasing atomic numbers in the group.

Solution 17

Since the size of the atom increases down the group, the ionic radii will also increase. Hence, the order of increasing atomic numbers in the group is Z < Y < X.

Question 18

Explain why are the following statements are not correct:

(i) All groups contain metal and non-metal.

(ii) Atoms of elements in the same group have same number of electron(s).

(iii) Non-metallic character decreases across a period with increase in atomic number.

(iv) Reactivity increases with atomic number in group as well as in a period.

Solution 18

(i) All groups do not contain both metals and non-metals. Group I and II contain only metals.

(ii) Atoms of elements in the same group have same number of valence electrons. They have same number of electrons present in their outermost shell.

(iii) The non-metallic character increases across a period with increase in atomic number. This is because across the period, the size of atom decreases and the valence shell electrons are held more tightly.

(iv) On moving from left to right in a period, the reactivity of elements first decreases and then increases, while in groups, chemical reactivity of metals increases going down the group whereas reactivity of non-metals is decreases down the group.

Question 19

Match the atomic number 19,15,8,4 and 2 with each of the following:

(i) A metal of valency one

(ii) A solid non-metal of period 3

(iii) A rare gas

(iv) A gaseous element with valency 2

(v) An element of group 2

Solution 19

(i) A metal of valency one = 19

(ii) A solid non-metal of period 3 = 15

(iii) A rare gas = 2

(iv) A gaseous element with valency 2 = 8

(v) An element of group 2 = 4

Question 20

Complete the following sentences choosing the correct word or words from those given in brackets at the end of each sentence:

i. The properties of the elements are a periodic function of their _____ (atomic number, mass number, relative atomic mass).

ii. Moving across a _____ of the periodic table, the elements show increasing _____ character (group, period, metallic, non-metallic).

iii. The elements at the bottom of a group would be expected to show _____ metallic character than the element at the top (less, more).

iv. The similarities in the properties of a group of elements are because they have the same _____ (electronic configuration, number of outer electrons, atomic numbers).

Solution 20

(i)The properties of the elements are a periodic function of their atomic number.

(ii)Moving across a period of the periodic table, the elements show increasing non-metallic character.

(iii)The elements at the bottom of a group would be expected to show more metallic character than the elements at the top.

(iv)The similarities in the properties of a group of elements are because they have the same number of outer electrons.

Question 21

Give reasons for the following:

The size of a Cl^- ion is greater than the size of a Cl atom.

Solution 21

An anion is formed by the gain of electrons. In the chloride ion, the number of electrons is more than the number of protons. The effective positive charge in the nucleus is less, so the less inward pull is experienced. Hence, the size expands.

Question ii

Give reasons for the following:

Argon atom is bigger than chlorine atom.

Solution ii

The inert gas argon is the next element after chlorine in the third period.

In a period, the size of an atom decreases from left to right due to an increase in nuclear charge with an increase in the atomic number. However, the size of the atoms of inert gases is bigger than the previous atom of halogen in the respective period. This is because the outer shell of inert gases is complete. They have the maximum number of electrons in their outermost orbit; thus, electronic repulsions are maximum. Hence, the size of the atom of an inert gas is bigger.

Question iii

Give reasons for the following:

Ionisation potential of the element increases across a period.

Solution iii

Ionisation potential of the element increases across a period because the atomic size decreases due to an increase in the nuclear charge, and thus, more energy is required to remove the electron(s).

Question (iv)alkali metal good raducing agent

Solution iv

Because they one e- in valece shell

Question 22

Name the element which has:

two shells, both of which are completely filled with electrons?

Solution 22

Neon (Atomic number = 10)

Electronic configuration = 2,8

Question

Name the element which has:

the electronic configuration 2, 8, 3?

Solution

Electronic configuration = 2, 8, 3

Hence, atomic number = 13

The element having atomic number 13 is Aluminium.

Question

Name the element which has:

a total of three shells with five electrons in its valence shell?

Solution

The element has a total of three shells; hence, the element belongs to the third period.

Five valence electrons indicate that the element belongs to the fifth group (VA).

Hence, the element is phosphorus.

Question

Name the element which has:

a total of four shells with two electrons in its valence shell.

Solution

The element has a total of four shells; hence, the element belongs to the fourth period.

Two valence electrons indicate that the element belongs to the second group (IIA).

Hence, the element is calcium.

Question 2

Name the element which has:

twice as many electrons in its second shell as in its first shell?

Solution

Twice as many electrons in its second shell as in its first shell indicates electronic configuration 2,2

From the electronic configuration, the total number of electrons is 4.

We know that

Number of electrons = Number of protons = Atomic number

The element with atomic number 4 is beryllium.

Question 23

State the number of elements in Period 1, Period 2 and Period 3 of the periodic table. Name them.

Solution 23

Period 1:

Number of elements = 2

Hydrogen, helium

Period 2:

Number of elements = 8

Lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon

Period 3:

Number of elements = 8

Sodium, magnesium, aluminium, silicon, phosphorus, sulphur, chlorine, argon

Question

What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 3?

Solution

A common feature of the electronic configuration of the elements at the end of Period 2 and Period 3 is that the atoms have 8 electrons in their outermost shell.

Question

If an element is in Group 17, it is likely to be ______ [metallic/non-metallic] in character, while with one electron in its outermost energy level (shell), then it is likely to be _______ [metallic/non-metallic].

Solution

If an element is in Group 17, it is likely to be non-metallic in character, while with one electron in its outermost energy level (shell), then it is likely to be metallic.

Chapter 1 - Periodic Table, Periodic Properties and Variations of Properties Exercise Intext 3

Question 1

(a) Define the term 'ionization potential'.

(b) Represent it in the form of an equation. In which unit it is measured?

Solution 1

(a) The energy required to remove an electron from a neutral isolated gaseous atom amd convert it into a positively charged gaseous ion is called Ionization energy or ionization potential.

(b) M(g)+ I.E M⁺(g)+ e^-

M can be any element

It is measured in electron volts per atom. It's S.I unit kJmol^-1.

Question 2

Ionisation Potential values depend on

a. atomic size

b. nuclear pull. Explain.

Solution 2

Ionisation potential values depend on

a. Atomic size: The greater the atomic size, the lesser the force of attraction. Electrons of the outermost shell lie further away from the nucleus, so their removal is easier and the ionisation energy required is less.

b. Nuclear charge: The greater the nuclear charge, greater is the attraction for the electrons of the outermost shell. Therefore, the electrons in the outermost shell are more firmly held because of which greater energy is required to remove them.

Question 3

State the trends in ionization energy:

(a) across the period

(b) down the group

Solution 3

(a) Ionization energy increases as we move from left to right across a period as the atomic size decreases.

(b) Ionization energy decreases down a group as the atomic size increases.

Question 4

Name the elements with highest and lowest ionization energies in first three periods

Solution 4

Helium has the highest ionization energy of all the elements while Sodium has the lowest ionization energy in first three periods.

Question 5

Arrange the elements of second and third period in increasing order of ionization energy.

Solution 5

Second period: Lithium < Beryllium < Boron < Carbon < Nitrogen < Oxygen < Fluorine < Neon

Third Period:Sodium < Magnesium < Aluminum < Silicon < Phosphorus < Sulphur < Chlorine < Argon

Question 6

(a) Define the term electron affinity.

(b) Arrange the elements of second period in increasing order of electron affinity. Name the elements which do not follow the trend in this period.

Solution 6

(a) Electron affinity is the energy released when a neutral gaseous atom acquires an electron to form an anion. Unit kj/mol

(b) Second period: Lithium < Boron < Carbon < Oxygen < Fluorine

Neon, Nitrogen and Beryllium do not follow the trend.

Question 7

Electron affinity values generally ----- across the period left to right and ------down the group top to bottom.

Solution 7

Electron affinity values generally increase across the period left to right and decrease down the group top to bottom.

Question 8

Define the term 'Electronegativity'. State its unit.

Solution 8

Electronegativity is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.

Electronegativity is a dimensionless property; hence, it has no unit.

Question

Among the elements given below, the element with least electronegativity is

(i) Lithium, (ii) Boron, (iii) Carbon, (iv) Fluorine

Solution

Correct option - (i).

The element with least electronegativity is lithium.

Question 9

Explain the following :

(a) Group 17 elements are strong non-metals, while group I elements are strong metals.

(b) Metallic character of elements decreases from left to right in a period while it increases in moving down a group.

(d) The reducing power of element increases down in the group while decreases in a period.

(e) Size of atoms progressively becomes smaller when we move from sodium (Na) to chlorine (Cl) in the third period of the periodic Table.

Solution 9

(a) On moving across a period, nuclear pull increases because of the increase in atomic number, and thus, the atomic size decreases. Hence, elements cannot lose electrons easily. Hence, Group 17 elements are strong non-metals, while Group 1 elements are strong metals.

(b) On moving across a period, nuclear pull increases because of the increase in atomic number, and thus, the atomic size decreases. Hence, elements cannot lose electrons easily. Hence, Group 17 elements are strong non-metals, while Group 1 elements are strong metals. Down a group, the atomic size increases and the nuclear charge also increases. The effect of an increased atomic size is greater as compared to the increased nuclear charge. Therefore, metallic nature increases as one moves down a group, i.e. they can lose electrons easily.

(c) The atomic size of halogens is very small. The smaller the atomic size, the greater the electron affinity, because the effective attractive force between the nucleus and the valence electrons is greater in smaller atoms, and so the electrons are held firmly.

(d) The reducing property depends on the ionisation potential and electron affinity of the elements. In a period, from left to right in a horizontal row of the periodic table, the atomic size decreases and the nuclear charge increases, so the electron affinity and ionisation energy both increase. Hence, the tendency to lose electrons decreases across the period from left to right and thus the reducing property also decreases across the period from left to right.

The electron affinity and ionisation potential decrease along the group from top to bottom. Hence, the tendency to lose electrons increases, and thus, the reducing property also increases along the group from top to bottom.

(e) In a period, the size of an atom decreases from left to right. This is because the nuclear charge, i.e. the atomic number increases from left to right in the same period, thereby bringing the outermost shell closer to the nucleus. Therefore, considering the third period given above, it has been found that sodium is the largest in size, while chlorine is the smallest.

Question10

Name the periodic property which relates tothe

(i) Amount of energy required to remove an electron from an isolated gaseous atom.

(ii) Character of element which loses one or more electrons when supplied with energy.

(iii) Tendency of an atom to attract the shared pair of electrons.

Solution 10

(i) Ionization energy

(ii) Metallic character

(iii) Electronegativity

Question 11

This question refers to the elements of the periodic table with atomic numbers from 3 to 18. Some of the elements are shown by letters, but the letters are not the usual symbols of the elements.

3 4 5 6 7 8 9 10

A B C D E F G H

11 12 13 14 15 16 17 18

I J K L M N O P

Which of these

a. are the most electronegative element

b. is a halogen

c. is an alkali metal

d. is an element with valency 4

e. have least ionisation energy

f. have least atomic size in Period 3

Solution 11

(a) G (due to the smallest atomic size).
(b) G and O as both have outermost electronic configuration 5
(c) A and I as both have outermost electronic configuration ns¹.
(d) D (2,4)
(e) I as alkali metals have least ionisation energy. Also, ionisation energy decreases with an increase in the atomic size that decreases on moving down the group.
(f) O, as halogens have the least atomic size.

Question 12

A group of elements in the Periodic Table are given below (boron is the first member of the group and thallium is the last).

Boron, Aluminium, Gallium, Indium, Thallium

Answer the following questions in relation to the above group of elements:

(a) Which element has the most metallic character?

(b) Which element would be expected to have the highest electronegativity?

(d) The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.

(e) Will the elements in the group to the right of this boron group be more metallic or less metallic in character? Justify your answer.

Solution 12

(a) Thallium. Because the metallic character increases down the group, thallium will have the most metallic character.

(b) Boron. Electronegativity decreases down the group as the size increases; hence, boron will be the most electronegative atom.

(c) Three. The number of electrons present in the valence shell is the same for each group. Hence, all these elements and thallium will have 3 valence electrons.

(d) BCl₃

(e) Since metallic character decreases from left to right and non-metallic character increases from left to right, elements in the group to the right of this boron group will be less metallic in character.

Chapter 1 - Periodic Table, Periodic Properties and Variations of

Properties

Exercise Intext 3

Question 1

(a) Define the term 'ionization potential'.

(b) Represent it in the form of an equation. In which unit it is measured?

Solution 1

(a) The energy required to remove an electron from a neutral isolated gaseous atom amd convert it into a positively charged gaseous ion is called Ionization energy or ionization potential.

(b) M(g)+ I.E M⁺(g)+ e^-

M can be any element

It is measured in electron volts per atom. It's S.I unit kJmol^-1.

Question 2

Ionisation Potential values depend on

a. atomic size

b. nuclear pull. Explain.

Solution 2

Ionisation potential values depend on

Question 3

State the trends in ionization energy:

(a) across the period

(b) down the group

Solution 3

(a) Ionization energy increases as we move from left to right across a period as the atomic size decreases.

(b) Ionization energy decreases down a group as the atomic size increases.

Question 4

Name the elements with highest and lowest ionization energies in first three periods

Solution 4

Helium has the highest ionization energy of all the elements while Sodium has the lowest ionization energy in first three periods.

Question 5

Arrange the elements of second and third period in increasing order of ionization energy.

Solution 5

Second period: Lithium < Beryllium < Boron < Carbon < Nitrogen < Oxygen < Fluorine < Neon

Third Period:Sodium < Magnesium < Aluminum < Silicon < Phosphorus < Sulphur < Chlorine < Argon

Question 6

(a) Define the term electron affinity.

(b) Arrange the elements of second period in increasing order of electron affinity. Name the elements which do not follow the trend in this period.

Solution 6

(a) Electron affinity is the energy released when a neutral gaseous atom acquires an electron to form an anion. Unit kj/mol

(b) Second period: Lithium < Boron < Carbon < Oxygen < Fluorine

Neon, Nitrogen and Beryllium do not follow the trend.

Question 7

Electron affinity values generally ----- across the period left to right and ------down the group top to bottom.

Solution 7

Electron affinity values generally increase across the period left to right and decrease down the group top to bottom.

Question 8

Define the term 'Electronegativity'. State its unit.

Solution 8

Electronegativity is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.

Electronegativity is a dimensionless property; hence, it has no unit.

Question

Among the elements given below, the element with least electronegativity is

(i) Lithium, (ii) Boron, (iii) Carbon, (iv) Fluorine

Solution

Correct option - (i).

The element with least electronegativity is lithium.

Question 9

Explain the following :

(a) Group 17 elements are strong non-metals, while group I elements are strong metals.

(b) Metallic character of elements decreases from left to right in a period while it increases in moving down a group.

(d) The reducing power of element increases down in the group while decreases in a period.

(e) Size of atoms progressively becomes smaller when we move from sodium (Na) to chlorine (Cl) in the third period of the periodic Table.

Solution 9

Question10

Name the periodic property which relates tothe

(i) Amount of energy required to remove an electron from an isolated gaseous atom.

(ii) Character of element which loses one or more electrons when supplied with energy.

(iii) Tendency of an atom to attract the shared pair of electrons.

Solution 10

(i) Ionization energy

(ii) Metallic character

(iii) Electronegativity

Question 11

This question refers to the elements of the periodic table with atomic numbers from 3 to 18. Some of the elements are shown by letters, but the letters are not the usual symbols of the elements.

3 4 5 6 7 8 9 10

A B C D E F G H

11 12 13 14 15 16 17 18

I J K L M N O P

Which of these

a. are the most electronegative element

b. is a halogen

c. is an alkali metal

d. is an element with valency 4

e. have least ionisation energy

f. have least atomic size in Period 3

Solution 11

Question 12

A group of elements in the Periodic Table are given below (boron is the first member of the group and thallium is the last).

Boron, Aluminium, Gallium, Indium, Thallium

Answer the following questions in relation to the above group of elements:

(a) Which element has the most metallic character?

(b) Which element would be expected to have the highest electronegativity?

(d) The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.

(e) Will the elements in the group to the right of this boron group be more metallic or less metallic in character? Justify your answer.

Solution 12

(a) Thallium. Because the metallic character increases down the group, thallium will have the most metallic character.

(b) Boron. Electronegativity decreases down the group as the size increases; hence, boron will be the most electronegative atom.

(c) Three. The number of electrons present in the valence shell is the same for each group. Hence, all these elements and thallium will have 3 valence electrons.

(d) BCl₃

10th class civics

Chapter 1

Question 1

Name the two types of authority in the federal set up……

answer :

Central government
State government.

Question 2

Name the law making bodies….

answer :

Lok sabha and rajya sabha.

Question 3

Main constituent of indian parliament…

Answer:

President.
Lok sabha.
Rajya sabha.

Question 4.

Two house ...indian parliament.

Answer:

Lok sabha and rajya sabha are the two houses.

Question 5

Maximum strength of the lok sabha….

Answer.

552 members

Question 6:Composition of lok sabha…….

Maximum members 552.

Elected from states: 530

Elected from Union territories: 20

Nominated by the president from anglo indian community: 2.

Question 6:

Who is empowered to summon……..lok sabha?

Answer:

The president of india.

Question 7

Members nominate in lok sabha…..?

Answer:

The president may nominate 2 members to lok sabha.

Question 8.

How are the members elected …..lok sabha?

Answer:

The members of lok sabha are directly elected by the people with the help of universal adult franchise.

Question 9

Quorum for lok sabha…

Answer:

A quorum implies the maximum number of members required to transact the business of the house. The quorum of lok sabha is one-tenth of the total membership of each house.

Question 10.

How are the speaker D. speaker…...elected?

Answer:

The speaker of the lok sabha is elected from among ruling party’s own members soon after the newly elected for the first time. The deputy speaker is elected in the same way as the speaker.

Question 11

Who presides …...lok sabha

Answer:

Speaker of the lok sabha

Question 12

Occasion of president’s address…?

Answer:

In case of disagreement between the two houses.
In case more than 6 months have elapsed without the bill being passed by the other house.

Question 13

Who presides ……...joint sitting?

Answer:

The speaker of the lok sabha.

Question 14

Rajya sabha member election

The members of rajya sabha elected by the elected members of the state legislative assemblies in accordance with a system of proportional representation by means of a single transferable vote.

Question 15

Who presides over the rajya sabha?

Answer:

The vice president of india.

Question 16

Who presides …………...in the absence of vice president?

Answer:

The deputy chairman performs all functions and duties of the chairman in his absence.
Question 17.

Mention any ……..equal power with lok sabha?

Answer:

The lok sabha and rajya sabha enjoys equal power in the matter of amendment to the constitution, the authorities of the two houses are equal. Amendment has to be passed by 2/3rd majority in each house.

Question 18

Advantages of lok sabha……………?

Answer:

Members are directly elected.
It controls the executive.
Vote of no-confidence passed in the lok sabha.

Question 19.

What do we mean when we say that the rajya sabha is a permanent body?

Answer :

The rajya sabha is a permanent house, as it is not subject to dissolution. One third of its members retire at the end of every second year. And new members are elected to fill the vacant seats.

Question 20

Term of rajya sabha member?

Answer.

The rajya sabha is a permanent house, hence it cannot be dissolved. Each member is elected for a term of six

question 21

Name the body………...rajya sabha members.

Answer.

The members of the rajya sabha are elected by the elected members of state legislative assemblies in accordance with a system of proportional representation by means of a single transferable vote.

Question 22

What is the maximum gap ………...sessions?

Answer:

Maximum six months.

Question 23.

Ex- officio chairperson.

Answer:

The vice president.

Question 24

Adjournment motion

Answer:

An adjournment motion means a proposal to lay aside all other business and take up a definite matter of urgent importance eg. death of several persons, a daring dacoity, some natural calamity, and communal tension.

Question 25.

Name the lists………………….the states.

Answer:

Union list
State list
Concurrent list.

Question 26.

Mention two circumstances ……………………….vacant.

Answer.

If a member, resign his seat by writing to the speaker or the chairman, as the case may be.
If a member, without permission of the house, is absent from all meetings for a period of 60 days.

Question 27.

Mention provisions …………………..money bills.

Answer.

Money bills can only be introduced in the Lok sabha.
The rajya sabha may withhold the bill for 14 days.
After 14 days the bill is deemed to be passed.

Question 28.

Which bodies have the right………………...such laws?

Answer:

Both the parliament and state legislature have the right to make laws on subjects mentioned in the concurrent list. In case of conflict between a central and state law, the law made by union parliament shall prevail.

Question 29

Who decides……..not?

Answer:

The speaker decides whether a particular bill is a money bill or not.

Question 30:

Mention any circumstances ……………………….a state subject.

Answer:

Under the following circumstances…

When the rajya sabha declares by a resolution passed by 2/3rd majority that a state list subject has assumed national importance.

Class 10 – Biology – chapter Photosynthesis

A. Multiple Choice Type

1.(b), 2.(b), 3.(b), 4.(c), 5.(a), 6.(a), 7.(d), 8.(b), 9.(a)

B. Very short answer type

1. Name the following

(a) Producers

(b) Chloroplast

(c)A.T.P

(d)Glucose

(e)Green plants

(f) Respiration

(g)Stroma

(h)Phloem

(a) Iron

(b) Stroma

(d)Oxygen

(e) Phloem

Descriptive type 4.Mention one difference

(a)Light-NADPH,ATP,and O2

Dark-Glucose,

(b)Producers-Autotrophic

Consumers-Heterotrophic

(c)Grass-Autotrophic

Grasshopper-Heterotrophic

C.Short answer type

1.True/False

(a) false

Dark reaction of photosynthesis occurs during daytime

(b)True

(c)False

Green plants are producers.

(d)False

Respiration results in loss of dry weight of the plants.

(e)False

Photosynthesis stops at a temperature of above 40°C

(f) True

(g) True

h) True

2. Fill in the blanks

(a)Grana

(b)Iodine solution

(c)Chloroplast

(d)Calvin cycle

(e)Sucrose

3.True /False

(a)True

Photosynthesis increases with the light intensity up to a certain limit, and then it gets stabilized. But if at this point the carbon dioxide concentration is increased, the photosynthesis also increases photo and again get stabilized.

(b)False

maximum suitable temperature when the photosynthesis occurs best is 35°Cand after which the rate of photosynthesis falls and stops above 40°C. Others uppermost limit the enzymes are destroyed.

The photosynthesis does continue although the immerse leaf receives low levels of sunlight and concentration of carbon dioxide dissolved in water is also low.

(d)False

Plant detaching of the leaves of a potted plant can occur during day by keeping it in a dark room for about 2 to 3 days.

(e)False

Dark reaction doesn't mean that it occurs only at night. It means it does not depend on light.

(f)True

Because the starting point of every food chain is always a plant which produces its own food through photosynthesis.

4. Correct order

Photons, grana, water molecules, hydrogen and hydroxyl ions, oxygen

PHOTOSYNTHESIS

(a)Oxygen gas is released

(b) Takes place during day time

(c)A constructive process

(d)Sunlight is required.

RESPIRATION

(a)Carbon dioxide is released

(b)Takes place during day as well as night time.

(c)A destructive process

(d)Sunlight is not required

6.Complete the following food chains

(i)Grass-grasshopper-snake-eagle

(ii)Grass-mouse-snake-peacock

7.Non-green plants such as fungi and bacteria obtain their nourishment from decaying organic matter in their environment. This matter comes from dead animals and plants, which in their own turn word dependent on photosynthesis.

8.Photosynthesis is the ultimate source of energy for all living beings. It is the only process which releases oxygen into the atmosphere and we no that oxygen is the life supporting gas. But photosynthesis is possible only due to the presence of chlorophyll in green plants. Thus all life owes its existence to chlorophyll.

(1)to kill the cells

(2)remove chlorophyll

(3)iodine

(4)blue black

(5) brown

10.Oxygen is not a waste product because all organisms required for the existence including the plants which require it at night.

D.Descriprive type

1.(a) Photosynthesis-It is the process by which living plant cells, containing chlorophyll, produce food substances from carbon dioxide and water, by using light energy.

(b)Thylakoids-These are the flattened sacks in chloroplasts which contain chlorophyll.

(c)Chloroplast-These are minute oval bodies bounded by a double membrane containing chlorophyll.It is a part of plant cell.

(d)Photolysis of water-Splitting of water molecules into hydrogen and oxygen in the presence of light and grana.

(e)Polymerisation of water-the process when several glucose molecules are transformed to produce one molecule of starch is called Polymerisation.

2(a)Guard cells-opening and closing of stomata for exchange of gases.

(b)Cuticle-allow light to enter freely

(c)Chlorophyll-trapping of Sunlight

(d)Stomata-exchange of gases

(e)Xylem tissue-conduction of water

(f)Phloem-translocation of food

3.Give reasons

(a)It is necessary to please plant in the dark before starting an experiment on photosynthesis to destarch the leaf.

(b)It is not possible to demonstrate respiration in green plants kept in sunlight because both respiration and photosynthesis are going simultaneously.

(c)Most leaves have the upper surface more green and shiny than the lower surface because the first surface of the leaves have more chloroplast which help in photosynthesis. Also the thick cuticle layer on the process of the leaf makes it shiny.

(d)(1) to kill the cells

(2) to remove chlorophyll

a.Place some water plants in a beaker containing pond water and cover them by a short stemmed funnel.

b.Invert a test tube full of water over the stem of the funnel.

c. Play store operators in the sun for a few hours. Bubbles of the gas will collect in the test tube.

d.When sufficient gas collected then test gas by introducing a glowing splinter into the test tube.

e. A glowing splinter burst into flame which shows the presence of oxygen.

E. Structured/Aplication skill type

(a)1.Photons of light

2. Oxygen

3. Glucose

4. Xylem

(b)

A indicates transpiration

B indicates upward conduction of water and minerals

2(a) Food chain

(b)eagle,peacock

(d)oxygen

3(a)To show that chlorophyll is necessary for photosynthesis

(b)To destarch the leaves

(c)Write the equation from page no.67 second column.

(d)Only the green parts of the leaf will turn blue black showing the presence of starch.

(e)Diagram is on page no 67 fig.6.1

4.(a) To prove that carbon dioxide is necessary for photosynthesis.

(b)Yes,lime water will absorb carbon dioxide and leaf will get to know carbon dioxide for photosynthesis.

(c)KOH will be taken.

(d)Yes,we will destarch the leaves of the plant before starting the experiment.Destarching means removal of starch and it can be done by keeping the plant in darkness for 2 to 3 days. It is necessary otherwise plant will not show the expected result.

5.Diagram-fig6.2A and B

(a)Photosynthesis

(b)Definition is already written in Descriptive 1(a)

(c)Snail is kept in test test tube baby so that it will evolve carbon dioxide and photosynthesis will occur.

(d)Because respiration and photosynthesis are occurring simultaneously and carbon dioxide is continuously produced by snail.

(e)Hydrilla

Class X Biology

Chapter 4

Absorption by Roots : The Processes Involved Exercise

Exercise -1

Question 1

Absorption of water by the plant cells by surface attraction is called:

a) Diffusion

b) Osmosis

c) Imbibition

d) Endosmosis

Solution 1

c) Imbibition

Question 2

A plant cell placed in a certain solution got plasmolysed. What was the kind of solution?

a) Isotonic sugar solution

b) Hypotonic salt solution

c) Hypertonic salt solution

d) Isotonic salt solution

Solution 2

c) Hypertonic salt solution

Question 3

The state of a cell in which the cell wall is rigid and stretched by the increase in volume due to the absorption of water is called

a) Flaccidity

b) Turgidity

c) Capillarity

d) Tonicity

Solution 3

b) Turgidity

Question 4

Which one of the following is a characteristic NOT related with the suitability of the roots for absorbing water?

a) Tremendous surface area

b) Contain cell sap at higher concentration than the surrounding water

c) Root hairs have thin cell walls

d) Grow downward into the soil

Solution 4

d) Grow downward into the soil

Question 5

Movement of molecules of a substance from the region of their higher concentration to the region of their lower concentration without the involvement of a separating membrane, is called:

a) Osmosis

b) Diffusion

c) Active transport

d) Capillarity

Solution 5

b) Diffusion

Question 6

Osmosis and diffusion are the same except that in osmosis there is

a) a freely permeable membrane

b) a cell wall in between

c) a selectively permeable membrane in between

d) an endless inflow of water into a cell

Solution 6

c) a selectively permeable membrane in between

Question 7

The highest water potential (capacity to move out to higher concentrated solution) is that of

a) Pure water

b) 10% salt solution

c) Honey

d) 50% sugar solution

Solution 7

a) Pure water

Question 8

The space between the cell wall and plasma membrane in a plasmolysed cell is filled with

a) isotonic solution

b) hypotonic solution

c) hypertonic solution

d) water

Solution 8

d) water

Question 9

What is responsible for guttation?

a) Osmotic pressure

b) Root pressure

c) Suction pressure

d) Capillarity

Solution 9

b) Root pressure

Question 10

The most appropriate characteristic of semi-permeable membrane is that

a) it has minute pores

b) it has no pores

c) it allows the solute to pass through but not the solvent

d) it allows a solvent to pass through freely but prevents the passage of the solute

Solution 10

d) it allows a solvent to pass through freely but prevents the passage of the solute

Question 11

Name the following:

(a) The condition of a cell placed in a hypotonic solution.

(b) Process by which intact plants lose water in the form of droplets from leaf margins.

(c) Process by which water enters root hairs.

(d) The tissue concerned with upward conduction of water in plants.

(e) The term for the inward movement of solvent molecules through the plasma membrane of a cell.

(f) The process by which molecules distribute themselves evenly within the space they occupy.

(g) The pressure which is responsible for the movement of water molecules across the cortical cells of the root.

Solution 11

(a) Turgidity

(b) Guttation

(c) Osmosis

(d) Xylem

(e) Endosmosis

(f) Diffusion

(g) Root pressure

Question 12

Give the equivalent terms for the following:

(a) Pressure exerted by the cell contents on the cell wall.

(b) The condition in which the cell contents are shrunken.

(c) Loss of water through a cut stem.

Solution 12

(a) Turgor pressure

(b) Flaccidity

(c) Bleeding

Question 13

Complete the following statements:

(a) Hypotonic solution is one in which the solution kept outside the cell has lower solute concentration than __________ the cell.

(b) Active transport is one in which the ions outside the roots move in with expenditure of energy __________.

(c) The bending movements of certain flowers towards the sun and the sleep movements of certain plants at night are examples of _____.

Solution 13

(a) the fluids inside

(b) from the region of their lower concentration outside to the region of their higher concentration inside

(c) turgor movements

Question 14

Fill in the blanks by choosing the correct alternative from those given in brackets:

(a) When placed in a more concentrated solution, the cell contents will ........... (shrink/swell up)

(b) The pressure by which the ............. molecules tend to cross the semi-permeable membrane is called osmotic pressure. (salt/water)

(c) Active transport is in a direction .............. to that of diffusion. (opposite/same)

Solution 14

(a) shrink

(b) water

(c) opposite

Question 15

Match the terms in column I those in column II

	Column I	Column II
a	Xylem	(i) semi-permeable
b	Phloem	(ii) permeable
c	Cell membrane	(iii) downward flow of sap
d	Root pressure	(iv) upward flow of water
e	Cell wall	(v) guttation

Solution 15

	Column I	Column II
a	Xylem	(iv) upward flow of water
b	Phloem	(iii) downward flow of sap
c	Cell membrane	(i) semi-permeable
d	Root pressure	(v) guttation
e	Cell wall	(ii) permeable

Question 16

Differentiate between the following :

(a) Plasmolysis and deplasmolysis

(b) Turgor pressure and wall pressure

(c) Guttation and bleeding

(d) Turgidity and flaccidity

Solution 16

(a)

Plasmolysis

Deplasmolysis

1. It refers to the shrinkage of the cytoplasm and withdrawal of the plasma membrane from the cell wall caused due to the withdrawal of water when placed in a hypertonic solution.

2. In Plasmolysis, the cell becomes flaccid.

1.Deplasmolysis is the recovery of a plasmolysed cell when it is placed in water, wherein the cell's protoplasm again swells up due to the re-entry of water.

2. In deplasmolysis, the cell becomes turgid.

(b)

Turgor pressure	Wall pressure
Turgor pressure is the pressure of the cell contents on the cell wall.	Wall pressure is the pressure exerted by the cell wall on the cell content.

(c)

Guttation	Bleeding
Guttation is the process by which drops of water appear along leaf margins due to excessive root pressure.	Bleeding is the loss of cell sap through a cut stem.

(d)

Turgidity	Flaccidity
1. It is the state of a cell in which the cell cannot accommodate any more water and it is fully distended.	1. It is the condition in which the cell content is shrunken and the cell is not tight.

Question 17

What is the difference between flaccid and turgid? Give one example of flaccid condition in plants.

Solution 17

The cell is said to be turgid when the plant cell wall becomes rigid and stretched by an increase in the volume of vacuoles due to the absorption of water when placed in hypotonic solution. On the other hand, the cell is said to be flaccid when the cell contents get shrunken when the cell is placed in hypertonic solution and the cell is no more tight. Flaccidity is the reverse of turgidity.

Example Weeds can be killed in a playground by sprinkling excessive salts around their base.

A plant cell when immersed in hypertonic solution like salt solution for about 30 minutes will become flaccid or limp.

Question 18

Give reasons for the following:

(a) If you sprinkle some common salt on grass growing on a lawn, it is killed at that spot.

(b) If you uproot a plant from the soil, its leaves soon wilt.

(c) It is better to transplant seedlings in a flower-bed in the evening and not in the morning.

(d) A plant cell when kept in a hypertonic salt solution for about 30 minutes turns flaccid.

(e) Potato cubes when placed in water become firm and increase in size.

Solution 18

(a) Common salt when sprinkled on the grass causes the Plasmolysis of grass cell ultimately leading them to death. Hence, if we sprinkle some common salt on grass growing on a lawn, it is killed at the spot.

(b) If a plant is uprooted, the leaves continue losing water by transpiration, but there is no more water absorbed the roots. This does not allow the compensation for the loss of water by transpiration; hence the leaves of the uprooted plant wilt soon.

(c) Transplantation causes stress to the seedlings. If the seedlings are transplanted in the morning, they would have to immediately bear the additional stress of excessive transpiration occurring during the hot afternoon. Transplantation in the evening helps the seedlings to adjust for a longer time during the night (cooler temperatures) because the quantity of water absorbed exceeds the loss of water through transpiration. Therefore, it is better to transplant seedling in a flower bed in the evening and not in the morning.

(d) In a hypertonic solution, the solution outside the cell has higher solute concentration than the fluids inside the cell. Therefore, water flows out from the plant cell due to exosmosis. The cytoplasm shrinks and the plasma membrane withdraws away from the cell wall and this the cell becomes flaccid. Hence a plant cell when kept in a hypertonic salt solution for about 30 minutes turns flaccid.

(e) Potato cubes contain excess of salts and sugars as compared to the water in which the cubes are placed. Hence, due to endosmosis, water from the surrounding enters the potato cubes making them firm and increasing their size.

Question 19

Mention whether the following statements are true (T) or false (F) and give explanation in support of your answer.

(a) Plasmolysis is reverse of deplasmolysis.

(b) Guttation is another name for bleeding in plants.

(c) Soaked seeds burst three seed coats

(d) If the phloem of a twig is removed keeping the xylem intact, the leaves of a twig wilt.

(e) Guttation in plants occurs maximum at mid-day.

(f) Dry seeds when submerged in water swell up due to endosmosis.

Solution 19

(a) True.

Plasmolysis occurs due to outflow of water from the cell when placed in hypertonic solution due to which the cytoplasm shrinks away from the cell wall. On the other hand, deplasmolysis is the result of the re-entry of water into the plasmolysed cell when placed in hypotonic solution due to which the protoplasm again swells up pressing tight against the cell wall.

(b) False.

Guttation is the process by which drops of water appear along leaf margins due to excessive root pressure whereas bleeding is the loss of cell sap through a cut stem.

(c) False.

There is only one seed coat in a seed.

(d) False.

The leaves of the twig remain turgid since its xylem is intact and xylem is responsible for water conduction in plants.

(e) False.

Guttation occurs due to excessive root pressure. It is maximum when root pressure is maximum which occurs in the early mornings or at night. This is because during these times, transpiration is very low and water absorption is very high.

(f) False.

Dry seeds when submerged in water swell up due to imbibitions. On contact with water dry seeds imbibe water and swell up.

Question 20

Give two examples of turgor movements in plants.

Solution 20

Examples of turgor movements in plants:

(i) In Mimosa pudica, a sensitive plant, the stimulus of touch leads to loss of turgor at the base of the leaflets and at the base of the petioles called pulvinus. This causes the folding and drooping of leaves of the plant.

(ii) The leaves of insectivorous plants close up to entrap a living prey. When the insect come in contact with the leaf, it loses it turgor hence closing the leaves of the plant.

(iii) The bending movements of certain flowers towards the sun.

(Any two)

Question 21

Explain the mechanism of the closing and opening of the stomata.

Solution 21

The closing and opening of the stomata depends on the turgidity of the guard cells. Each guard cell has a thicker wall on the side facing the stoma and a thin wall on the opposite side. Guard cells contain chloroplasts. As a result of the synthesis of glucose during photosynthesis and some other chemical changes, the osmotic pressure of the contents of the guard cells increases and they absorb more water from the neighbouring cells, thus becoming turgid. Due to turgor, the guard cells become more arched outwards and the aperture between them widens, thereby opening the stoma.

At night or when there is shortage of water in the leaf, the guard cells turn flaccid and their inner rigid walls become straight, thus closing the stomatal aperture.

Question 22

Concentration of mineral nutrient elements is higher inside the root-hairs than in the surrounding soil. How do roots take them in from the soil?

Solution 22

If the concentration of mineral nutrient elements is higher inside the root-hairs than in the surrounding soil, then roots take them in from the soil by 'active transport'. In active transport, the mineral ions are forcibly carried from the surrounding soil i.e. the region of their lower concentration into the roots i.e. the region of their higher concentration through the cell membrane by expenditure of energy. This energy is supplied by the cell in the form of ATP.

Question 23

Explain how soaked seeds swell up and burst their seed coats.

Solution 23

When soaked in water, the seeds swell up due to imbibition and endosmosis. During these two processes water enters the cell. Due to endosmosis, at some point, the seed coat is unable to bear the turgor pressure and hence, the seed coat bursts.

Question 24

Leaves of the sensitive plant wilt and droop down on a slight touch. What mechanism brings about this change?

Solution 24

Leaves of the sensitive plant wilt and droop down on a slight touch due to turgor movement. Petiole of sensitive plant is held up by turgid pulvinus tissue. The stimulus of touch leads to loss of turgor at the base of the leaflets and at the base of the petioles i.e. pulvinus. The cells of the lower side of pulvinus lose water and the petiole collapses. This causes the wilting and drooping of the leaves.

Question 25

What is transpirational pull? How is it caused?

Solution 25

As water is lost from the leaf surface by transpiration, more water molecules are pulled up due to the tendency of water molecules to remain joined i.e. cohesion. This produces a continuous column of water throughout the stem which is known as 'transpiration pull'. A negative pressure or tension is produced in the xylem that pulls the water from the roots and soil. Transpirational pull is an important force which causes the ascent of sap.

Question 26

The following diagram represents a plant cell after being place in a strong sugar solution.

Guidelines 1 to 5 indicate the following:

(1) Cell Wall

(2) Strong Sugar Solution

(3) Protoplasm

(4) Large Vacuole

(5) Nucleus

(a) What is the state of the cell shown in the diagram?

(b) Name the structure which acts as a selectively permeable membrane.

(c) If the cell had been placed in distilled water instead of strong sugar solution, which feature would not have been seen?

(d) Name any one feature of this plant cell which is not present in an animal cell.

Solution 26

(a) The cell is flaccid i.e. it is plasmolysed.

(b) Plasma Membrane

(c) Plasmolysis would not occur and flaccidity would not be seen i.e. the protoplasm would not have shrunken away from the cell wall.

(d) Cell Wall is absent in animal cell.

Question 27

A leaf cell of a water plant was placed in a liquid other than pond water. After sometime, it assumed a shape as shown below:

(a) Give the term for the state of the cell it has acquired.

(b) Comment on the nature (tonicity) of the liquid surrounding the cell.

(c) Redraw in the space provided, the diagram of the cell if it is soon placed in ordinary water for some time.

Solution 27

(a) Flaccid Cell

(b) The liquid is hypertonic solution. It has higher solute concentration outside the cell than the fluids inside the cell. (c)

Question 28

The diagram below represents a layer of epidermal cells showing a fully grown root hair. Study the diagram and answer the questions that follow:

Selina Solutions Icse Class 10 Biology Chapter - Absorption By Roots The Processes Involved

a. Name the parts labelled A, B, C and D.

b. The root hair cell is in a turgid state. Name and explain the process that caused this state.

c. Mention one distinct difference between the parts labelled A and B.

d. Draw a diagram of the above root hair cell as it would appear when a concentrated solution of fertilizers is added near it.

Solution 28

A - Cell wall

B - Cell membrane

C - Cytoplasm

D - Nucleus

b. A root hair gets turgid because of the absorption of water from the surrounding. Absorption of water by root hair is achieved by the process of osmosis. The concentration of water in the surrounding is more than that of the interior of the cell; this causes the water from the surrounding to move in because of endosmosis.

Cell wall	Cell membrane
The cell wall of a root hair is freely permeable and allows both salt and water to pass through.	The cell membrane of a root hair is semi-permeable and does not allow large dissolved salt molecules to pass through.

Question 29

Two potato cubes each 1 cm3 in size, were placed separately in two containers (A and B), the container A having water and the other (B) containing concentrated sugar solution. After 24 hours when the cubes were examined, those placed in water were found to be firm and had increased slightly in size and those placed in concentrated sugar solution were found to be soft and somewhat decreased in size. Use the above information to answer the questions that follow:

(a) Account for the firmness and increase in the size of the potato cubes placed in water.

(b) Account for the softness and decrease in size of the potato cubes which were placed in sugar solution.

(c) Name and define the physical process being investigated in this experiment.

Solution 29

(a) Water is hypotonic to the potato cells, due to which endosmosis occurs and water enters the potato cells. The protoplasm swells up pressing tight against the cell wall. The cells are fully distended i.e. turgid. This causes the firmness and increase in the size of the potato cubes when placed in water.

(b) Sugar solution is hypertonic to the potato cells, due to which exosmosis occurs and water flows out of the potato cells. The potato cell loses its distended appearance, the cytoplasm shrinks and the plasma membrane withdraws from the cell wall. The cells become limp or flaccid. This causes the softness and decrease in size of the potato cubes when placed in sugar solution.

(c) The process being investigated is osmosis. Osmosis is the diffusion of water molecules across a semi-permeable membrane from a more dilute solution (with a lower solute concentration) to a less dilute solution (with a higher solute concentration).

Question 30

Study the diagram given below and answer the questions that follow:

(a) Name the process being studied in the above experiment.

(b) Explain the process mentioned in (a) above

(c) Why is oil placed over water?

(d) What do we observe with regard to the level of water when this set up is placed in (1) bright sunlight (2) humid conditions (3) windy day?

(e) Mention any three adaptations found in plants to foster the process mentioned in (a) above

Solution 30

(a) The process of water absorption by plant roots through osmosis is being studied here.

(b) A root-hair contains cell sap which contains higher concentration of salts as compared to outside soil water. This difference sets off osmosis and outside water diffuses into the root-hair. From the cell bearing root-hair, water passes into adjoining cells one after another to finally the xylem vessels.

(c) The surface of water was covered with oil to prevent any loss of water by evaporation.

(d) Roots absorb water and hence, the level of water in set up A falls down. Since the surface of water was covered with oil, there will be no effect of factors such as bright sunlight, humid conditions and windy day on the given set up. Hence, the level of water

(e) Adaptations in plants to foster the process of absorption of water by plant roots:

· Large surface area provided by rootlets and root hairs

· Root hairs containing cell sap at a higher concentration than that of the surrounding water

· Root hairs with thin walls

Question 31

Show by a series of diagrams, the change which a plant cell will undergo when placed in

(a) Hypertonic salt solution and

(b) Hypotonic salt solution.

Solution 31

(a)

(b)

Question 32

Study the experimental setup in the figure and then answer the questions that follow.

(a) What phenomenon is being studied by this setup?

(b) Explain the phenomenon mention in (a) above.

(d) What will you observe in the setup after about half an hour? Give reasons for your answer.

Solution 32

(a) Osmosis

(b) Osmosis is the movement of water molecules from their region of higher concentration (dilute solution) to their region of lower concentration (concentrated solution) through a semipermeable membrane.

(c) A semipermeable membrane is a membrane which allows the passage of molecules selectively. It allows a solvent such as water molecules to pass through it freely but prevents the passage of the solute (sugar or salt molecules in solution).

(d) Water molecules will continue to pass from 5% sucrose solution to 10% sucrose solution through the semipermeable membrane due to osmosis. This will continue till the concentration of water molecules becomes the same in both ends of the setup.

Question 33

A candidate in order to study the process of osmosis has taken 3 potato cubes and put them in 3 different beakers containing 3 different solutions. After 24 hours, in the first beaker the potato cube increased in size, in the second beaker the potato cube decreased in size and in the third beaker, there was no change in the size of the potato cube. The following diagram shows the result of the same experiment.

(a) Give the technical terms of the solutions used in the beakers 1, 2 and 3.

(b) In beaker 3, the size of the potato cube remains the same. Explain the reason in brief.

(d) What is osmosis?

(e) How does a cell wall and a cell membrane differ in their permeability?

Solution 33

(a) Solution 1 - Hypotonic solution

Solution 2 - Hypertonic solution

Solution 3 - Isotonic solution

(b) In beaker 3, the solution present is an isotonic solution, i.e. the relative concentration of water molecules and solutes is the same in the solution as well as inside the cell. There is no movement of water molecules across the cell membrane. Hence, the size of potato cubes remains the same.

(d) Osmosis is the diffusion of water molecules across a semi-permeable membrane from the region of dilute solution (i.e. a lower solute concentration) to the region of concentrated solution (i.e. a higher solute concentration).

(e) The cell wall is freely permeable to all substances, while the cell membrane is selectively permeable and allows only certain substances to enter or exit the cell.

Physical Education Class X

Chapter 1

Very short answers

1.The term growth implies an increase in size. When the body or any part is described as having growth it usually means that it has become larger and heavier. It is thus we say growth of arms, brain, muscles or the body in general. Growth means increase or addition in size, height, length or weight and can be measured.

2. Development implies certain qualitative changes. These are the changes in character leading to maturity of improvement in functioning. Arms grow large but also develop by undergoing certain changes which equip them for better work. Development means change in shape,form or structure so as to improve in working or functioning.

3. :-Growth doesn't continue throughout life whereas development is a continuous process.

:-Growth is cellular and can be measured accurately whereas development is functional or organizational,thus a subjective interpretation of one's changes.

4. :-Heridity(explain)

:- Environment(explain)

5. Acc. to Jersild," Adolescence is a period through which a growing person makes transition from childhood to maturity."

6. The stages of Growth and Development are:

:- Infancy stage(from birth to 5years)

:- Childhood stage(from 5to 12 years)

:- Adolescence stage(from 12 to 19 years)

:-Adulthood stage (19 to 65 years)

:-Old age(60 years onwards)

7. In this period, rapid physical changes happen. Puberty brings remarkable sex difference which changes the shape of an individual,such as breast development, muscular changes,bone hardening, moustaches and change in voice, blackheads, pimples and acne over skin etc.

8. :-Aggressive and violent behaviour (explain)

:-Wastage of time (explain)

9. :-Providing healthy environment (explain)

:-Proper sex education (explain)

10. :-Youth stage(from 19 to 35 years)(explain)

:-Adult stage (from 35 to 65 years)(explain)

Match the following:

"Sequence"

3, 7, 8, 5, 2, 1, 4, 9, 6

Short answers:

1. Done

2. Done

3. Two differences are already discussed,rest four are:

:-Growth is quantitative process whereas Development is qualitative process.

:-Growth is one of the aspects of development process whereas Development is wider and comprehensive term.

:-Growth changes are physical and physiological whereas development changes are functional, psychological etc.

:-Growth is purely physical term like change in size, length, height and weight of an individual whereas development implies overall changes in shape,form or structure resulting in improved working or functioning.

4. Heredity, environment, gender, nutritional, physical activity, health problems and age(all points with explaination)

5. Childhood stage (from 5 to 12 years)

:-Early childhood stage(from 5 to 7 years)

:-Middle childhood stage (7 to 10 years)

:-Later childhood stage (from 11 to 12 years)(all points with explaination)

6. Adolescence changes:

:- Physical changes

:-Psychological changes

:-Emotional changes

:-Social changes(all points with explaination)

7. Problems of teen:

:-Aggressive and violent behaviour

:-wastage of time

:-Friends given importance

:-Overconfident and hide mistakes

:-Wrong sexual desires

:-Lavish expenses(explain all points)

:-Proper knowledge of Adolescence psychology

:-providing healthy environment

:-proper sex education

:-correction and checking of mistakes

:- proper use of time

:-mode of education(explain all points)

9. Done

Long answers:

1. Done

2. Infancy stage (from birth to 5 years):

:-pre-natal stage (from conception till birth)

:-babyhood stage(from birth to 5 years)(explain all points)

Childhood stage(discussed)

3. Done

4. Done

CHAPTER-2

Very short answers:

1. Acc. to J.B.Nash,"Physical education is that field of education which deals with big muscle activities and their related responses."

2. Acc. to J.F.William,"Aim of physical education is complete living through wholesome development of human personality."

3. The objectives of physical education:

:-Physical development

:-Psychological development

:-Social development

:-Emotional development (explain all points)

Match the following:

Sequence:

3, 4, 1, 2

Short answers:

1. Physical Development :-The objective is wholesome physical growth through physical activities.Also to improve neuromuscular responses and leads to maximum organic growth. To guide a person to make his body strong,well shaped, good looking, good working of internal organs, good health and improves the physical personality.

Social Development: The objective is to follow the rules, regulations, traditions and laws of society. To develop the social qualities like cooperative behaviour, friendship, togetherness, honesty, obedience, sincerity, tolerance, adjustment, leadership, boldness, self-control, self-discipline etc. To be an ideal citizen and a useful member of the society.

2. To counter the declining fitness trend,many schools and districts have taken a closer look at their physical education programmes. These programmes are recognizing the academic benefits of quality fitness programmes through varied exercises focusing on overall health of the children.

3. The current trend in physical education instruction has focussed less on fun and team sports and more on getting children healthy. Instructors have had to outline and define goals specific to increasing life-long health. They have identified three cores areas for focus : current fitness levels,educating health matters and teaching how to plan for long-term exercise. The first key is a focus on fitness. The overall quality of physical education classes has shifted from a fun release of energy to an increased scope of physical health.

Long answers:

1. Done

2. Done

3. B.P.E(Bachelor of physical education) : physical education teacher in school, fitness instructor etc., M.P.E(Master of physical education) : lecturer in senior secondary schools or in colleges etc. , M.S.S(Master of sports science) : lecturer in college etc. , NIS diploma (National institute of sports diploma in a specific game) : specific game coach in school, college, University, sports department etc.

CHAPTER-3

Very sorry answers:

1. It is classification of human body according to it's shape and physique. It was developed by W.H.Sheldon. He classified the human body in terms of three extreme body types : Endomorphic, Mesomorphic and Ectomorphic.

2. Ectomorph :- lean and long, with difficulty in building muscles.

Endomorph : big, high body fat, often pear-shaped, with a high tendency to store body fat.

Mesomorph : muscular and well-built, with a high metabolism and responsive muscle cells.

3. Done(explain in full)

4. Done(explain in full)

Match the following:

Sequence:

3, 1, 2, 4

Short answers:

1. W.H Sheldon (explain)

2. Done (explain in full)

3. Done (explain in full)

4. Done(explain in full)

Long answers:

1. Done(explain all three body types in full)

2. Done(explain both separately in full)

CHAPTER-4

Very short answers:

1. Acc. to David.R.Lamb,"Physical fitness is the capacity to meet the present and potential physical challenges of life with success."

2. It is the ability to produce force or ability of muscles to overcome resistance.

3. It is the combination of circulatory and respiratory system to provide continuous flow of energy for long work-out with slow speed. Helpful for long distance races, Football, Hockey etc.

4. It is the combination of strength, speed and endurance ability for long duration with high speed. Helpful for fast games, middle distance races, Badminton, Tennis etc.

5. Passive flexibility and

Active flexibility (two types)

:-Static flexibility

:-Dynamic flexibility

6. It is the ability to overcome resistance with high speed. It provide forceful movement for short duration. Helpful for jumps,throws,power lifting etc.

Match the following:

Sequence:

2 , 4, 5, 6, 1, 3, 7

Short answers:

:-Total efficiency is improved

:-Better quality of work

:-Optimum growth and development

:-Better utilization of time

:-Healthy Environment

:-Good looking physique(explain all points)

2. Cardiovascular endurance, stamina and accuracy (explain all three)

3. Done(explain both separately)

4. Strength (done)

Types:

Static strength (also known as isometric strength. It is the ability to act against resistance from single position. Helpful for high power games like power lifting, pushing the wall etc.

:-Growth(It is the ability to overcome resistance with high speed. It provide forceful movement for short duration. Helpful for jumps, throws, power lifting etc.

5. Accuracy (It is the hitting the target to achieve goal or 100 percent perfection)

Balance (It is the ability to stay up-right or stay in control of the body movement on small place)

Two types of Balance:

Static Balance (It is balancing at ones stationary point)

Dynamic Balance (It is the ability to balance on moving point)

6. Parts of Speed:

Reaction Time(It is the time taken by the body to respond immediately after stimulus. It is the first reaction to bring the body into action)

Acceleration (It is the time taken by the body to reach to maximum speed)

Speed of Movement (It is the quickness of complete action or movement)

7. Football (Cardiovascular endurance),

Badminton (Stamina),

Long Jump (Power), 100m Sprint(Speed) and Gymnastics (Flexibility)

Long answers:

1. Done

2. Cardiovascular endurance, Stamina, strength, speed, flexibility, agility, balance and accuracy (explain all)

3. Stamina : It is the endurance where the anaerobic type of activity is done, when the intensity or speed is very fast. This endurance is for shorter duration and also known as muscular endurance as activity is performed in absence of oxygen with the help of stored energy in muscle glycogen. It produces a lot of fatigue and tiredness as it causes oxygen-debt. It is required for games and sports like Tennis, Badminton,Handball, Basketball, Volleyball, Middle distance races, Swimming etc.

Cardiovascular endurance : It is the endurance of aerobic nature where speed is slow. It delays fatigue,thus it is required for middle and long distance races like road cycling, cross-country, marathon race and it is required for almost all major games like Football, Hockey, Basketball, Handball etc.

4. Speed is the ability to perform movement at faster rate. It is basically dependent on heredity but can be improved through proper training. It depends upon the white muscle fibres(fast twitch). It is one of the important components for sprints(100m,200m and 400m) which can be measured through reflex test,short Sprint etc.

It is of three types:

:-Reaction Time

:-Acceleration

:-Speed of Movement (explain all three)

5. Done(explain both separately)

HOME

Class X- History and Civics

Chapter 1 (history)

Question 1

What is the nature of the revolt of 1857

Answer:

According to british point of view it was sepoys’ mutiny but according to indian nationalists it was first war of independence.

Quetion 2

Why was the revolt os 1857 hailed as first war of independence?

Answer

People of different catses, communities and religions came together for the first time and fought for independence.

Question 3

Mention two political causes of the first war of independence

Answer

Two political causes are

1. The british policy of annexation of kingdoms under the pretext of inefficient administration of the rulers

2. The doctrine of lapse introduced by lord dalhousie that imposed unisentimental law of no adoption policy for the rulers and lapse of kingdom into the hands of british in the absence of natural heir.

Question 4

Name two ways in which the british expanded their territorial power in india.

Answer:

1. British got right to diwani in 1765.

2. Doctrine of lapse.

3. Subsidiary allaince.

4. On the pretext of alleged misrule.

5. By outright wars

Question 5.

What is subsidiary allaince? Name the states annexed with the help of it.

Answer .

It was an agreement between the british east india company and the indian princely states by virtueof which these states lost their sovereignty to the british. Under this system, the indian rulers, who agreed to the subsidiary allaince.

1. Accepted the british as the supreme power

2. Agreed to maintain british troops at thier own cost

Hyderabad and mysore were the two states.

Question 6.

Explain the term doctrine of lapse. Name the two states annexed under this policy.

Answer

Policy of doctrine of lapse was followed by lord dalhousie. The doctrine meant that when a ruler of a dependent state died without a natural heir, the state is passed on to the english- company. States annexed were sambhalpur, nagpur, udaypur.

Question 7.

Who was nana saheb?what was his main grievance against british?

Answer

Nana saheb was the adopted son of Baji Rao II, the last peshwa the british refused to accept nana saheb, the adopted son as the last peshwa baji rao II as the ruler of the maratha and was refused to give the pension which his father was getting.

Question 8

Which policy was used against rani laxmi bai? Why rani luxmi became bitter enemy?

Answer:

The policy used against rani luxmi bai was doctrine of lapse. Rani luxmi bai became bitter enemy of british because her adopted son anand rao was not recognised as a lawful successor to the throne.

Question 9

State two anouncement which adveresly affected mughal empire?

Answer:

1. The successors of bahadur shah would not be permitted to use the red fort as thier palace.

2. The successors of bahadur shah would not be permitted to use the imperial title of mughal emperor

Question 10

Mention any two consequences of awadh annexation

Answer:

1. Several officials and soldiers lost thier jobs which brought unemployment.

2. The british took away lands from the taluqdars. These taluqdars became firm opponents of the british

Question 11

State any two cosequences of the dibanding of the armies of the annexed states.

Answer:

1.It brought large scale unemploment.

2. It also gave rise to poverty as large no. Of families got effected.

3. the people of awadh had to pay higher land revenue and additional taxes on food, houses, ferries and justice.

Question 12

Give the meaning of absentee sovereignty. Why was it resented by the idians?

Answer:

It means that india was being ruled by the british government from england, at a distance of thousands of miles.

The indians felt the india’s wealth was being drained to england and not utilised for their welfare.

Question 13

What were the apprehensions of indians about the introduction of the railways?

Answer:

It was looked down uponas a means to break social order and caste rules.people of all castes has to sit together in railway compartments. This was regarded as an attempt to interfere with the caste rules.

Question 14

Mention any two social reforms advocated by the british which affected the religion traditions of the indian people.

Answer:

Sati system and no permission to widow remarriage was prevailing in the society.

The british government passed the widow re marriage act in 1856 and sati system was defeated illegal by passing an act.

Question15

Mention any two measures which point to the policy of social discrimination followed by the british in india.

Answer:

1. British continued their policy of divide and rule

2. They believed in their racial superiority and they thought that a distance was maintained to preserve their authority over indians

3. They clearly used the attraction of the government service to create a split along religious lines among educated indians.

Question 16

Give two example to show how the british exploited resources of india.

Answer:

India was forced to export at cheaper rates raw materials like raw cotton and raw silk as duty free to british industries.

All trade and commerce had gone into the hands of the english.

Question 17

Give any two grievances of the peasantry against the british?
Answer:

1. The peasants were discontented with the official land revenue policy.

2. It was the peasantry that bore the heavy burden of exorbitant taxes to provide money for the trade and profits of the company.

Question 18

What did british do to reduce the landed aristocracy to poverty?

Answer:

1. Economic exploitation

2. Decay of indigenous industries

3. High taxation

4. The drain of wealth

5. Stagnation of agriculture

Question 19

General service enlistment act and provision that resented the indian soldiers

Answer:

This act hurt the sentiments of sepoys because according to the current religious beliefs of the hindus, travel across the seas was considered a sin. This act cause great resentment in the minds of the personnel of the begngal army.

Question 20

Mention any two grievances harboured by the indian soldiers which created an atmosphere favourable to the first war of independence.

Answer:

1. All higher posts were reserved for british in employment.

2. An indian soldier could not rise above the rank of subedar.

3. Indian soldier were required to serve in areas away from their homes without extra and additional bhatta.

Question 21.

Impact of defeat of british in first afghan war.

Answer:

The defeat in the first afghan war increased the self confidence of the indian soldiers, who felt, they could challenge the britain in india too.

Question 22

Immediate cause of the revolt of 1857.

Answer:

The immediate cause of the uprising was the use of greased cartridges in the rifles after biting the end of cartridge with their teeth. It was thought that the cartridges were greased with the fats of cow and pig. So both hindu and muslim soldiers refused to use these cartridges.

Question 23

Mangal pandey?

Answer:

Mangal pandey was a brahmin soldier, who refused to use the greased cartridges on 29^th march, 1857 and killed two english officers. He was hanged consequently, this resulted in general uprising in meerut, delhi, kanpur, lucknow and jhansi.

Question 24

What was the result of indian independence on the east india company?

Answer:

The first war of independence ended the east india company’s rule in india since the british statesmen thought it unwise to leave the government of vast country in the hands of private trading company.

Question 25

How was the army organised after the first war of independence?

Answer:

The portion of british indian soldiers was increased and different castes and creeds were mixed to avoid any other revolt.

Question 26.

Imapct of revolt of 1857 on peshwaship and mughal rule.

Answer :

1. With the death of bahadur shah II the mughal dynasty came to an end.

2. Nana saheb, the last peshwa had taken part in the uprising and had to flee to nepal after the failure of the uprising. So the office of peshwa also came to an end.

Question 27.

Mention any two drawbacks of the first war of independence.

Answer:

1. Lack of common plans

2. Lack of leadership

Class - X BIOLOGY

D. Long answer type

1.Due to the shortage of water the leaves droop down and loose their turgidity.This flaccid condition of leaves is called wilting. Some plants show wilting of their leaves at noon even when the soil is well watered because the rate of transpiration at that time is higher than the rate of absorption of water by the roots.

2.The stomata in most plants are more numerous on the lower surface of a leaf instead of being on the upper surface because lower surface is less exposed to sunlight as compared to upper surface.

3. Cover a potted rose plant.With a transparent polythene bag tied its mouth around the base of the stem of the plant in sunlight for an hour or two.Drops of water will soon appear on the inner side of the bag due to saturation of water vapour given out by the leaves.A similar empty polythene bag with its mouth tied and kept in sunlight will show no drops of water.This is a control to show that plants transpire water. Therefore this experiment demonstrate transpiration in rose plant.(Diagram is on page no.55,fig.5.1)

4. Photometer is a device which measures the rate of water intake by a plant,and this water intake is almost equal to the water lost through transpiration.

5.Lenticular transpiration is the transpiration which occurs through lenticels which are present on the old green stems of the plant. These are the minute openings which remain open all the time.

LENTICULAR TRANSPIRATION

a.It occurs through lenticels.

b. The amount of lenticular transpiration is very small.

STOMATAL TRANSPIRATION

a.It occurs through stomata.

b.the amount of stomatal transpiration is very large.

6.(a)The intensity of sunlight

(b) temperature

7.The huge quantities of water released into the atmosphere by stretches of fields and particularly forests through transpiration, which increases the moisture in the atmosphere and brings rain.

8.No,these are not the dew drops.These drops are actually the water drops which are coming out from the margins of the leaves in humid conditions due to the less rate of transpiration and excess amount of water present in the plant body.

9.(a)The rate of transpiration is directly affected by intensity of light.If the intensity of light is more the rate of transpiration will be more,if the intensity of light is less the rate of transpiration will be less.

(b)The rate of transpiration is inversely proportional to humidity.If the humidity is high the rate of transpiration will be less and if the humidity is less in the atmosphere, then the transpiration will be more.

E. Structured/Application Skill Type

1.(i) left uncoated because in this leaf transpiration occurs from both surfaces so it will be the most limp.

(ii) coated on both surfacesbecause both the sides of the leaf is covered by Vaseline so it shows least limping.

2(a) Transpiration

(b)To prevent evaporation from the surface of water.

(c)To measure the amount of lost water during transpiration.

(d) yes more rate of transpiration will be their. Inshot more loss of weight of plant.

3.(a) Ganong's photometer

Transpiration

Exercise A multiple choice type
Solutions
1(a) open stomata, dry atmosphere and moist soil
2(a) increase
3(d) atmosphere is dry and temperature is high
4(c) sunken stomata
5(d) hydathodes
6(d) transpiration
7(d) hot,dry and windy
8(a) stomata
9(c) loss of water, as water vapour, by a plant.

Exercise B
Very short answer type
1 Name the following:
(a) lenticels
(b) guttation
(c) potometer
(d) nerium
(e) ganong's potometer
(f) cuticle, stomata
(g) hydathodes
(h) guttation

2 fill in the blanks:
(a) vapour, aerial
(b) stomata, transpiration
(c) suction, water

C short answer type

1 functional activity
(a) hydathodes and guttation
(b) leaf spines and reduced transpiration
(c) lenticels and lenticular transpiration/diffusion of gases
(d) xylem and conduction of water

2(a)true or false
(1) false
Most transpiration occurs at midday
(2) true
(3) true
(4) false
Potometer is an instrument used for measuring the rate of transpiration in green plants.

3 Give suitable explanation for the following:
(a) Higher rate of transpiration is recorded on a windy day rather than on a calm day because transpiration increases with the velocity of wind. If the wind blows faster,the water vapour released during transpiration is removed faster and the area outside the leaf does not get saturated with water vapour.

(b) Excessive transpiration results in the wilting of leaves because the rate of transpiration exceeds the rate of absorption of water by the roots. Hence the cells lose turgidity.

(c) Out of total water absorbed by plants only a small quantity of this water is used by the plant in photosynthesis and other activities.The rest of it is almost lost to the atmosphere as water vapour as a result of transpiration. So, water transpired is the water absorbed.

(d) More transpiration occurs from the lower surface of a dorsiventral leaf because in a dorsiventral leaf more stomata are present on the lower surface as compared to upper surface.

(e) Cork and bark are made up of flattened dead cells with fatty substance which is impermeable to water and gases and thereby, help in preventing loss of water.

(f) Transpiration is a process in which water evaporates from a plant specially through the stomata of the leaves.In this way transpiration helps to low down the temperature of the plant in hot weather.When the body temperature rises sweat glands excrete small amount of water along with urea and salts to the surface of skin and it also cools the body by evaporation.So in this way perspiration and transpiration helps to cool the body temperature of the organism.

(g)On a bright sunny day the leaves of certain plants roll up because the rate of transpiration exceeds the rate of absorption of water by roots.

4 true or false
(a) true
Because potometer is attached by a leaf shoot which contains numerous stomata.
(b) true
Because both are the pores on plant body through which transpiration occurs.
(c) false
Because if humidity is high then transpiration is less and vice versa.
(d) true
Because it is an adaptation of plant to reduce transpiration.
(e) true
Because at that time the intensity of sunlight is more which favours transpiration.

5 Differentiate between guttation and bleeding
GUTTATION
1 It is a loss of water as droplets along the margins of leaves.
2 It occurs through hydathodes found at the end of veins.
BLEEDING
1 It is the direct flowing out of plant sap.
2 It occurs from the ruptured or cut surfaces of a plant.

Class - x English language

Total English -10

Chapter -1 is solved in the book
Chapter-2
Q.5 (a)1.was affected

2.made
3.fermented
4.became
5.working
6.converts
7.turns
8.packs
b) 1.up
2.of
3.away
4.in
5.into
6.over
7.after
8.for

c)1. The examination had begun before we reached the hall.
2.I don't care whether Manav join me or not.
3. As it is very cold,we can't wear cotton clothes.
4.Since you helped him ,he will be grateful to you.

d)1.Hardly had the train arrived when all rushed into the compartments.
2.There was a collision between a bus and a car.
3.How long can I bear it?
4.You cannot come with us for the picnic unless your father permits you.
5.We had never met each other since 2009.
6.The Commander ordered the soldiers not to give up and march on.
7.Put your tools away lest people should fall over them.
8.I wish I had been appointed to the post.
Chapter-3
Q.5.
a)1.doubled
2.shows
3.generated
4.was processed
5.compared
6.worst
7.collected
8.treated
b) 1.by
2.into
3.with
4.away
5.about
6.up
7.away
8.towards
c)1.As it was very hot I could not go out.
2.The room is too small to accommodate all of us.
3.The book that I borrowed from my neighbour is good.
4.Aditi was too terrified to speak

d)1. I suggested to my sister that we should go to the market the next day for shopping.
2.As he is poor,he cannot afford such expensive treatment.
3. Inspite of being rich man, he is not proud.
4.Bina inherited a big fortune from her father.
5.He pleaded for his ignorance of law.
6.It is believed that he was involved in the crime.
7.I wish I had taken my doctor's advice.
8.He not only passed the examination well but also won the first prize.
Chapter-4
Q.5 a)1.wants
2.disposal
3.adopted
4.mandated
5.will give
6.bringing
7.stopped
8.have seen that

b) 1. Under
2.down
3.after
4.over
5.on
6.up
7.for
8.without

c)1. Ankita as well as Kalyani is pretty.
2.Everybody knows that the shopkeeper is cunning.
3.I do not know why he is not coming to school.
4.He is poor however not a cheat.

d)1.Tagore was one of the most famous artists.
2.Unless you tell the truth ,you will be punished.
3.He asked if he might have a cup of milk.
4.If he is given some more time,he will complete this work by tomorrow.
5.We organised a function so that we may raise funds for the school.
6.Who has not heard of the Quit India Movement?
7.I prefer small towns to big cities.
8.Inspite of being too young she was appointed by them.
Chapter-5
Q.5 a)1.to control
2.published
3.shows
4. cools
5.are created
6.aid
7.understanding
8.help

b)1.on
2.by
3.aside/away
4.forth
5.through
6.on
7.up
8.under

c)1.I would not have completed the task but for Anu's help.
2.Mr Khosla cannot be late as he is punctual.
3.Kindly tell me why you did not complete your project.
4.We will wait for you till you come back.

d)1.The police not only kept a watch on his movements but also tapped his phones.
2.Everyone will admit that she is honest.
3.If you had not helped me I would not have succeeded.
4.He spent his whole life here since his birth.
5.The principal said,"I will look into the case."
6.Inspite of knowing him for long,I have not developed respect for him
7.John did not understand why Anita was annoyed with him.
8.Tom can run faster than anybody else in our team.

Class 10 – Biology – chapter Photosynthesis

A. Multiple Choice Type

1.(b)

2.(b)

3.(b)

4.(c)

5.(a)

6.(a)

7.(d)

8.(b)

9.(a)

B. Very short answer type

1. Name the following

(a) Producers

(b) Chloroplast

(c)A.T.P

(d)Glucose

(e)Green plants

(f) Respiration

(g)Stroma

(h)Phloem

(a) Iron

(b) Stroma

(d)Oxygen

(e) Phloem

Descriptive type 4.Mention one difference

(a)Light-NADPH,ATP,and O2

Dark-Glucose,

(b)Producers-Autotrophic

Consumers-Heterotrophic

(c)Grass-Autotrophic

Grasshopper-Heterotrophic

C.Short answer type

1.True/False

(a) false

Dark reaction of photosynthesis occurs during daytime

(b)True

(c)False

Green plants are producers.

(d)False

Respiration results in loss of dry weight of the plants.

(e)False

Photosynthesis stops at a temperature of above 40°C

(f) True

(g) True

h) True

2. Fill in the blanks

(a)Grana

(b)Iodine solution

(c)Chloroplast

(d)Calvin cycle

(e)Sucrose

3.True /False

(a)True

(b)False

maximum suitable temperature when the photosynthesis occurs best is 35°Cand after which the rate of photosynthesis falls and stops above 40°C. Others uppermost limit the enzymes are destroyed.

The photosynthesis does continue although the immerse leaf receives low levels of sunlight and concentration of carbon dioxide dissolved in water is also low.

(d)False

Plant detaching of the leaves of a potted plant can occur during day by keeping it in a dark room for about 2 to 3 days.

(e)False

Dark reaction doesn't mean that it occurs only at night. It means it does not depend on light.

(f)True

Because the starting point of every food chain is always a plant which produces its own food through photosynthesis.

4. Correct order

Photons, grana, water molecules, hydrogen and hydroxyl ions, oxygen

PHOTOSYNTHESIS

(a)Oxygen gas is released

(b) Takes place during day time

(c)A constructive process

(d)Sunlight is required.

RESPIRATION

(a)Carbon dioxide is released

(b)Takes place during day as well as night time.

(c)A destructive process

(d)Sunlight is not required

6.Complete the following food chains

(i)Grass-grasshopper-snake-eagle

(ii)Grass-mouse-snake-peacock

(1)to kill the cells

(2)remove chlorophyll

(3)iodine

(4)blue black

(5) brown

10.Oxygen is not a waste product because all organisms required for the existence including the plants which require it at night.

D.Descriprive type

1.(a) Photosynthesis-It is the process by which living plant cells, containing chlorophyll, produce food substances from carbon dioxide and water, by using light energy.

(b)Thylakoids-These are the flattened sacks in chloroplasts which contain chlorophyll.

(c)Chloroplast-These are minute oval bodies bounded by a double membrane containing chlorophyll.It is a part of plant cell.

(d)Photolysis of water-Splitting of water molecules into hydrogen and oxygen in the presence of light and grana.

(e)Polymerisation of water-the process when several glucose molecules are transformed to produce one molecule of starch is called Polymerisation.

2(a)Guard cells-opening and closing of stomata for exchange of gases.

(b)Cuticle-allow light to enter freely

(c)Chlorophyll-trapping of Sunlight

(d)Stomata-exchange of gases

(e)Xylem tissue-conduction of water

(f)Phloem-translocation of food

3.Give reasons

(a)It is necessary to please plant in the dark before starting an experiment on photosynthesis to destarch the leaf.

(b)It is not possible to demonstrate respiration in green plants kept in sunlight because both respiration and photosynthesis are going simultaneously.

(d)(1) to kill the cells

(2) to remove chlorophyll

a.Place some water plants in a beaker containing pond water and cover them by a short stemmed funnel.

b.Invert a test tube full of water over the stem of the funnel.

c. Play store operators in the sun for a few hours. Bubbles of the gas will collect in the test tube.

d.When sufficient gas collected then test gas by introducing a glowing splinter into the test tube.

e. A glowing splinter burst into flame which shows the presence of oxygen.

E. Structured/Aplication skill type

(a)1.Photons of light

2. Oxygen

3. Glucose

4. Xylem

(b)

A indicates transpiration

B indicates upward conduction of water and minerals

2(a) Food chain

(b)eagle,peacock

(d)oxygen

3(a)To show that chlorophyll is necessary for photosynthesis

(b)To destarch the leaves

(c)Write the equation from page no.67 second column.

(d)Only the green parts of the leaf will turn blue black showing the presence of starch.

(e)Diagram is on page no 67 fig.6.1

4.(a) To prove that carbon dioxide is necessary for photosynthesis.

(b)Yes,lime water will absorb carbon dioxide and leaf will get to know carbon dioxide for photosynthesis.

(c)KOH will be taken.

5.Diagram-fig6.2A and B

(a)Photosynthesis

(b)Definition is already written in Descriptive 1(a)

(c)Snail is kept in test test tube baby so that it will evolve carbon dioxide and photosynthesis will occur.

(d)Because respiration and photosynthesis are occurring simultaneously and carbon dioxide is continuously produced by snail.

(e)Hydrilla

Geography ch 6

Because areas have maximum rainfall ranging between 150cm to 200cm and experience temperature between 240C to 270C

Ans:-11 • Sal, Teak, sandalwood and myrobalan

Ans:-12 Some characteristics are:- i. They are suitable for wildlife some due to less rain, low temperature and snowfall. ii. These trees are mainly evergreen with needle shaped leaves, more wood and less leaves. iii. They are found in Eastern and western Himalayas (Kumaon Hills and Nilgires)

Ans:-13 • They have rainfall less than 25 cm and temperature ranging between 250C to 270 C

Ans:-14 i. Mangrove vegetation is characterized by breathing roots which act as respiratory organs. ii. These forests are very dense forests iii. Its stilt like roots remain submerged under water but can be seen at low tide. This tangled mass of roots help the plant to survive in the Shifting mud of Coastal region iv. Sundari is very important in this area (as species)

Ans: - 15 • It is also called as tidal forests or littoral forests (on -shore)

Ans:-16 ❖ Afforestation:- Planting more and more trees for the reduction of pollution. ❖ Deforestation:- Cutting down of tress and causing damage to environment

Ans: - 17 1. The features of forests of tropical evergreen forests are: dense growths of trees make it difficult for accessibility / large numbers of species of trees/ lack of pure stands/logs are heavy. 2. Temperatures are very high and heavy rainfalls make it unsuitable for living. 3. Lack of transport also makes it different to exploit.

Ans:-18. • Deciduous monsoon forests are found on the eastern part of south India as it receives rain of 150cm to 200cm, with a hot dry season from March to end of May, they shed their leaves then, hence they are deciduous.

Ans:-19 ❖ Rajasthan ❖ Punjab. Ans:- 20 ❖ Tidal forest ❖ Sundari trees

Ans:-21 (i) Its wood is very hard ,strong and durable (ii) It is used for boat building. (iii) Sundari is very important in tidal area sunderban delta has been named after it.

Ans:-22 • Trees are a source of raw material and trees release O2 and absorb Co2 which help in maintaining the environmental balance as industries release many harmful gasses which effect the temperature of earth’s atmosphere

Ans: - 23 • Himachal Pradesh • Kashmir for building houses • Railways sleeper

Ans:-24 • Tidal forest

Ans:-25 • 22% Ans: 26 (A)Because these forest have different variety of trees which shad there leaves at the different time and it always appear green so that that is way it is called as Evergreen. (B)Because they are found in the areas of heavy rainfall so for this reason they called as rainforest. (C)Its stilt like roots are remain submerged under water but can be seen at low tide. This tangled mass of roots help the plant to survive in the Shifting mud of Coastal region Ans:-27 (A)Delta region (B)Myrobalan (C)Deciduous monsoon forest

Ans:-28 (On book page no. 173)

Class 10 History

CHAPTER: 1

THE FIRST WAR OF INDEPENDENCE, 1857

1. (a). The rebellions are local, scattered and isolated. (b). They did not pose a serious challenge to Britishers.

2. i). It was the first mess uprising where every section of society participated. ii). It paved the way for rise of modern national movement.

3. i). Subsidiary alliance. ii). Doctrine of Lapse.

4. i). By Outright wars. ii). Subsidiary alliance. iii). Doctrine of Lapse. iv). Alleged Misrule.

5. i). System under which Indian rules had to accept British Supremacy. ii). They had to manage British troops on their own costs.

6. Hyderabad, Awadh.

7. Adopted Heirs of the king would not have any right to inherit the throne.

8. He was adopted son of Baji Rao II. He was not recognized as the ruler of Maratha.

9. His adopted son was not recognized a ruler of Jhansi.

10. Bahadur Shah’s successor would not be allowed to use imperial titles with their names and would be known as mere princes.

11. Alleged misrule.

12. i). Thousands of nobles, officers and soldiers were out of job. ii). British confiscated the status of zamindars.

13. They become a strong opponents of Britishers.

14. Absentee sovereignty means India was being ruled by British government from England at a thousand of miles. Indians felt that they were being ruled from England and not utilized for their welfare.

15. Orthodox Indians noted that in railway compartments the higher castes and lower castes were made to sit side by side. They believed that British had introduced some practices to defy the caste & religion.

16. Widow remarriage was abolished. Sati system was declared illegal.

17. i). Interference with Social Customs. ii). Taxing Religious Places.

18. India was made to accept readymade British goods either duty free or at nominal duty. Indian goods were unable to compete with cheaper goods. Raw materials of Indians were exported at less rates but sold at high rates..

19. i). Indian goods cannot compete with British goods. ii). Picnics were given low wage and artisans were not patronized.

20. i). Peasants were given low wages. ii). Peasants were forced to live in unhygienic conditions.

21. They confiscated the Indian lands with a reason that they did not have legal proofs for their lands.

22. According to it Hindu soldiers were required to go to overseas to fight with other countries. Crossing overseas were considered a taboo for them.

23. i). They were not given high ranks. ii). They were not given good wages.

24. It broke the myth of Indian soldiers that British troops could not be defeated.

25. The cartridges used in Enfield rifle were said to be greased with fat of cows and pigs. The greased paper had to be bitten off with the teeth before leading them in rifle. Cows were considered sacred for Hindus and pigs were considered taboo to Muslims.

26. First Brahmin soldier who refused to use Enfield rifles. He refused those cartridges and was hanged.

27. i). It ended East Indian Company’s rule. ii). Indian administration went directly to hand of Queen Victoria.

28. i). The strength of European troops were increased. ii). All weapons were kept in charge of Europe (Britishers).

29. Lord Canning.

30. Rule came to an end.

31. i). They will not interfere in religious matters of Indians. ii). Treat all Indians & European equal. 32. i). Lack of Planning. ii). Lack of Leadership.

CIVICS

Chapter 1: The Union Parliament

Short Answers:-

1. State government and Central Government .

2.Legislature

3. Lok Sabha, Rajya Sabha, The President

4. Lok Sabha and Rajya Sabha

5. 552 members.

6. The Lok Sabha consists of not more than 552 members – 530 members are selected from the States and 20 members from the Union Territories (UTs)and two members are from the Anglo-Indian community are nominated by the President.

7. The Lok Sabha can be dissolved by the President on the advice of Prime Minister.

8. The President.

9. Two members.

10. The members of the Lok Sabha are directly elected by the people on the basis of Universal Adult Franchise.

11. 1/10th of the total membership.

12. The Speaker and the Deputy Speaker of the Lok Sabha are elected from among its own members soon after the newly elected House meets for the first time.

13. The Speaker.

14. The President addresses both the Houses of Parliament assembled together for the first session after each General Election to the Lok Sabha and at the commencement of the first session of each year.

15. The Speaker.

16. (i). The Speaker is the presiding officer of Lok Sabha. (ii). The Speaker certifies a bill as a money bill. (iii). The Speaker maintains discipline in the House.

17. a). The Lok Sabha acts as the voice of the nation. b). It is the Lok Sabha which actually controls the Executive organ.

18. The members of Rajya Sabha are indirectly elected by the elected members of the State Legislative Assembly with the system of proportional representation by means of a single transferable vote. Vice President The members of Rajya Sabha elect among themselves a Deputy Chairman.

19. Deputy Chairman.

20. The Rajya Sabha is a permanent House. It cannot be dissolved and thus plays a major role during the period when the Lok Sabha is dissolved.

21. Impeachment of President.

22. (a). Motion of no-confidence against the government can be introduced and passed in the Lok Sabha. (b). Money bills can only be introduced in Lok Sabha.

23. The Rajya Sabha is a permanent body. It cannot be dissolved. The term of office for its members is 6 years. One-third of its members retire after every 2 years.

24. 6 years. One-third of its members retire after every 2 years.

25. State Legislative Assemblies.

26. 6 months.

27. Vice-President.

28. An Adjournment motion means a proposal to lay aside all other business and take up a definite matter of urgent importance.

29. If there is a deadlock between the two houses of Parliament on a non-money bill, the President may summon a joint session where the will of the Lok Sabha normally prevails as its strength is more than double than that of Rajya Sabha.

30.

31.

32. Union List, State List and Concurrent List.

33. (a). If a member resigns his seat by writing to the Speaker or to the Chairman, as the case may be. (b). if a member is disqualified on the basis of Anti-Defection Law.

34. Quorum means the minimum no. of members required to be present in order to enable the House to transact its business, i.e., 1/10th of total membership.

Zero Hour: The Zero Hour refers to the period which begins at 12 O’clock soon after the Question Hour and continues to the lunch break which begins at 1 O’clock. During the Zero Hour, members raise all types of questions without any permission or prior notice. 35. (a). Interpellation (b). Absence of Quorum.

Adjournment of the House means suspension of the utility of the House by the Speaker whereas prorogation means termination of the session of Parliament by the President.

36. (a). Interpellation (b). Vote of no-confidence (c). Adjournment motion

37. (a). It can be introduced in Lok Sabha only. (b). Lok Sabha can reject all or any of the recommendations made by the Rajya Sabha.

Money Bill

It can only be introduced in the Lok Sabha.

Non Money Bill

It can be introduced in both the Houses of Parliament.

2. The final decision is in the hands of Lok Sabha. Both the houses have equal powers but in case of deadlock, the will of Lok Sabha prevails. Lok Sabha Term : 5 years Rajya Sabha

6 years. But after every 2 years one-third of its members retire.

38. Both the Centre and the State have the right to legislate on the subjects in the Concurrent list.

In case of conflict, the central government enjoys an overriding position.

39. Speaker. 40. During the proclamation of State Emergency.

CHAPTER: 2

GROWTH OF NATIONALISM

1. Nationalism refers to feeling of oneness and common consciousness that emerges when people living in common territory shared the same historical, political and cultural background, have the same language, cultural value and consider themselves as one nation.

2. i). Loyalty of people was towards a particular king or kingdom. ii). Lack of Political stability. iii) Social evils were prevailing.

3. i). Economic exploitation of India. ii). Socio-religious reform movements.

4. i). Drain of wealth. ii). Indian crafts and arts were not patronized. iii). Heavy taxes were levied on Indian goods.

5. India was turned into colony, exporting raw material and importing finished goods. Peasants were ruthlessly tortured.

6. i). Exchange of ideas ii). Exposed true nature of Britishers.

7. Lord Lytton. It forbade vernacular papers not to write anything that would raise dissatisfaction against Britishers.

8. Lord Rippon. It arose the feeling of nationalism among Indians.

9. Times of India, The Tribune.

10. i). Impact of Western Education ii). Worked for abolition of Social Evils. iii). Fought for individual liberty and against social evils.

11. Raja Ram Mohan Roy, Jyotiba Phule.

12. Satya Shodak Samaj with aim of securing justice to weaker section of society.

13. It sought to abolish judicial disqualification based on race discrimination. This was resented by Britishers and they started Defense Association to defend their special privileges which provoked agitation by Indians.

14. Surendranath Banerjee.

15. i). Mass participation in public movement. ii). Creation of strong body of public opinion.

16. i). Indian Nation Conference ii). East Indian Association. 17. A.O. Hume in 1885.

18. Ist – 1885 – Mumbai – W.C. Banerjee IInd – 1886 – Kolkata – Dadabhai Naroji.

CHAPTER: 3

FIRST PHASE OF THE INDIAN NATIONAL MOVEMENT

1. 1885 – 1907

2. Surendranath Banerjee, Dadabhai Naoroji, Gopal Krishna Gokhle. 3. i). They believed that British rule had many benefits in modernization of country. ii). They would change the orthodox opinion of Indians.

4. i). Constitutional methods ii). Peaceful methods.

5. i). They have faith in British sense of justice of justice. ii). They believed that Britishers would help in modernization of country.

6. Social and economic backwardness of country.

7. Democratic.

8. i). They made use of press to criticize government policies. ii). They held meetings where speeches were made and resolution for popular demands were passed.

9. i). Reduction in land revenue and protection of peasants against unjust demands of Zamindars. ii). Availability of cheap credit to peasants through agriculture.

10. i). Abolition of Indian council. ii). Expansion of Legislative assemblies – both at the Centre and in Province.

11. i). Reduction in land revenue and protection of peasants against unjust demands of Zamindars. ii). Availability of cheap credit to peasants through agriculture.

12. i). A heavy tax should be imposed goods and government should give loans for development of iron, coal, paper and sugar industries in India. ii). Abolition of Salt Tax & Duty on sugar.

13. i). They created national awakening among people that they belonged to one common country. ii). They trained people in politics by popularizing the ideas of democracy.

14. They failed to draw masses into mainstream of national movement. They failed to realize that British were using Indian resources to increase their wealth.

15. Dadabhai Naoroji.

16. He founded East Indian Association in India. He put forward the India’s drain of wealth by writing Poverty & non British rule in India. 17. Dadabhai Naoroji as he fights for the cause of his country during his stay in England.

18. India’s wealth was being drained to England through various ways.

19. Dadabhai Naoroji.

20. Surendranath Banerjee.

21. License Act & Arms Act.

22. i). He played an important role in passage of Minto Morley reforms ii). He also served as member of Public Service Commission.

23. i). They created national awakening among people that they belonged to one common country. ii). They trained people in politics by popularizing the ideas of democracy

CHAPTER: 10

THE FIRST WORLD WAR

1. Nationalism refers to the feeling of unity where the people living in a region share same culture, history etc.

2. France wanted to get back Alsace and Lorraine from Germany.

3. Britain had created vast empire by requiring colonies in Asia and Africa. It resources markets, territories and people. Other countries of world like Germany too wanted to acquire colonies in Asia and Africa.

4. Triple alliance – France, Britain, Russia. Signatory countries – Germany, Italy, Austria, Hungary.

5. Sarajevo crisis was murder of Archduke Ferdinand by Serbian people at Sarajevo Capital of Bosnia.

6. Serbia 7. Austria

8. Germany, Turkey.

9. Germany had left Britain and France far behind in production of Iron and Steel and in many other manufactures.

10. Germany, France, Russia, Austria, Britain.

11. Because German U ship had sunk British ship Lusitania. Many Americans were killed.

12. Because all countries of the world were directly or indirectly involved in it.

13. Russia

14. Russia: Russia had suffered many losses in war. The day after Bolshevik government came into power under leadership of Lenin, it issued Decree on Peace with proposal to end war.

15. Argument signed between allies and Germany in June 28, 1919. 16. Austria got separated from Hungary and formed independent State.

17. U.S.A.

18. Formation of U.N.O. Division of world into two power blocks: U.S.A. and U.S.S.R.

19. This weakened position of industrialized countries after first World War, which provided an impetus to freedom movement in colonial countries like Asia & Africa.

20. Denmark got Danzig and Holstein from Germany.

21. After World War I in 1920.

22. To maintain peace, to protect countries from future wars.

23. To maintain peace, to protect countries from future wars. 24. Germany and Soviet Union.