Class 9 Hydrogen Exercise 6(A) Chapter-6

Question 1

Justify the Position of Hydrogen in the periodic table.

Answer 1

Hydrogen is the first element in the periodic table. Its atomic number is 1, and it has only one electron in its valence shell. So, it belongs to the first group and the first period of the periodic table.

Question 2

Why does hydrogen show dual nature?

Answer 2

Hydrogen shows dual nature because it resembles the alkali metals of Group IA and the halogens of Group VIIA.

Question 3

Compare hydrogen with alkali metals on basis of:

(i) Ion formation

(ii) Reducing power

(iii) Reaction with oxygen

(iv) Oxide formation

Answer 3

(i) Each of them can form a cation by loss of an electron.

H → H⁺ + e^–

Li →Li⁺ + e^–

(ii) Both alkali metals and hydrogen act as reducing agents.

CuO + H₂ → Cu + H₂O

CuO + Na → Cu + Na₂O

(iii) Hydrogen burns in oxygen to form its oxide. It burns with a pop sound.

2H₂ + O₂ → 2H₂O

Alkali metals also burn vigorously when heated in oxygen to form their respective oxides.

Lithium forms monoxide.

4Li + O₂ → 2Li₂O

(iv) Hydrogen burns in oxygen to form its oxide. It burns with a pop sound.

2H₂ + O₂ → 2H₂O

Alkali metals also burn vigorously when heated in oxygen to form their respective oxides.

Lithium forms monoxide.

4Li + O₂ → 2Li₂O

Question 4

In what respect does hydrogen differ from:

(i) alkali metals

(ii) halogens?

Answer 4

(i) Oxides of alkali metals are basic in nature, whereas the oxide of hydrogen H₂O is a neutral oxide.

(ii)Hydrogen atom has only one shell, but halogens have two or more shells.

Question 5

Give the general group study of hydrogen with reference to

(i) valence electrons

(ii) burning

(iii) reducing power

Answer 5

(i) Hydrogen has one valence electron in its outermost orbit.

(ii) Hydrogen burns in oxygen to form its oxide. It burns with a pop sound.

2H₂ + O₂ → 2H₂O

(iii) Hydrogen acts as a reducing agent.

CuO + H₂ → Cu + H₂O

Question 6

Why hydrogen was called ‘inflammable air’?

Answer 6

Hydrogen was called inflammable air because of its combustible nature.

Question 7

State some sources of hydrogen.

Answer 7

In the free state, hydrogen is found in traces in the earth’s crust and atmosphere.

And In the combined state, plant and animal tissues are made of compounds of hydrogen with carbon, oxygen and nitrogen.

Question 8

Compare hydrogen and halogens on the basis of:

(i) physical state

(ii) ion formation

(iii) valency

(iv) reaction with oxygen

Answer 8

(i) Like halogens (fluorine and chlorine), hydrogen too is a gas.

(ii) Both show a tendency to form anions because they are one electron short of the nearest inert gas configuration.

H + e^– → H^–

Cl + e^– →Cl^–

(iii) Both have valency 1.

(iv) Hydrogen reacts with oxygen to form neutral oxide, H₂O. Halogens react with oxygen to form acidic oxides like Cl₂O and Cl₂O₇.

Question 9

Which metal is preferred for preparation of hydrogen.

(i) from water?

(ii) from acid?

Answer 9

(i) Reactive metals such as potassium, sodium and calcium.

(ii) Magnesium, aluminium, zinc and iron.

Question 10

(i) Write the reaction of steam with red hot iron.

(ii) Why this reaction is considered as reversible reaction?

(iii) How the reaction can proceed continuously?

Answer 10

(i) 3Fe + 4H₂O ⇋ Fe₃O₄ + 4H₂

(ii) The reaction is reversible because if hydrogen formed is not removed, then the iron oxide formed is reduced back to iron.

(iii) Because the reaction is a reversible reaction, equilibrium is attained at 700°C. At this stage, the amount of reactants and products does not change.

Question 11

why zinc and aluminium are considered to have unique nature. Give balanced equations to support your explanation.

Answer 11

They react with acids and can even react with hot concentrated alkalis to form hydrogen and a soluble salt.

Zn + 2NaOH → Na₂ZnO₂ + H₂

2Al + 6NaOH→ 2Na₂Al O₃ + 3H₂

Oxides and hydroxides of zinc and aluminium are amphoteric. They react with both bases and acids to give salt and water.

ZnO + 2HCl → ZnCl₂ + H₂O

ZnO + 2NaOH →Na₂ZnO₂ + H₂O

Question 12

Write balanced equations for the following:

(i) Iron reacts with dil. HCl

(ii) Zinc reacts with caustic soda solution

(iii) Lead reacts with potassium hydroxide

(iv) Aluminium reacts with fused sodium hydroxide

Answer 12

(i) Fe +2 HC l → FeCl₂ + H₂

(ii) Zn + 2NaOH → Na₂ZnO₂ + H₂

(iii) Pb + 2KOH → K₂PbO₂ + H₂

(iv) 2Al + 6NaOH→ 2Na₂Al O₃ + 3H₂

Question 13

Write the balanced equations and give your observations when the following metals react:

(i) Sodium with cold water

(ii) Calcium with cold water

(iii) Magnesium with boiling water

(iv) Magnesium with steam

Answer 13

(i) The reaction is highly exothermic and vigorous with the evolution of hydrogen.

2Na + 2H₂O →2NaOH + H₂

(ii) Calcium sinks in water and the reaction is less vigorous.

Ca + 2H₂O → Ca(OH)₂ + H₂

(iii) Magnesium reacts slowly with boiling water and forms a base, magnesium hydroxide, liberating hydrogen gas.

Mg + 2H₂O →Mg(OH)₂ + H₂O

(iv) Magnesium burns in steam with an intense white light liberating hydrogen gas and white ash, i.e. magnesium oxide.

Mg + H₂O → MgO + H₂

Question 14

(i) Under what conditions iron reacts with water.

(ii) Give the balanced equation of the reaction.

(iii) What is noticed if the products are not allowed to escape?

Answer 14

(i) Iron is less reactive than zinc, but red hot iron reacts with steam, forming triferric tetra-oxide and hydrogen gas.

(ii) 3Fe + 4H₂O ⇋ Fe₃O₄ + 4H₂

(iii) If the product formed, i.e. hydrogen is not removed, then the iron oxide formed is reduced back to iron.

Question 15

From the knowledge of activity series, name a metal which shows the following properties

(i) It reacts readily with cold water.

(ii) It displaces hydrogen from hot water.

(iii) It displaces hydrogen from dilute HCl.

(iv) It forms a base which is insoluble in water.

Answer 15

(i) Sodium

(ii) Magnesium

(iii) Zinc

(iv) Calcium

Question 16

Complete the following word equations:

(i) Sodium hydroxide + zinc → hydrogen + _________

(ii) Calcium + water → calcium hydroxide + _________

Answer 16

(i) Sodium hydroxide + zinc → hydrogen + sodium zincate

(ii) Calcium + water → calcium hydroxide + hydrogen

Chapter-6 Hydrogen Study of First Element Selina Solutions Exercise – 6(B)

Question 1

Hydrogen can be prepared with the metal zinc by using:

(i) acid

(ii) alkali

(iii) water

Give an equation in each case.

Answer 1

(i) Zn + HCl → ZnCl₂ + H₂

(ii) Zn + 2NaOH → Na₂ZnO₂ + H₂

(iii) Zn + H₂O → ZnO + H₂

Question 2

For laboratory preparation of hydrogen, give the following:

(a) materials used

(b) method of collection

(d) fully-labelled diagram

Answer 2

(a) Granulated zinc, dilute HCl or dil. H₂SO₄

(b) It is collected by the downward displacement of water.

(d)

Question 3

(a) Name the impurities present in hydrogen prepared in the laboratory.

(b) How can these impurities be removed?

Answer 3

(a) Hydrogen sulphide, sulphur dioxide, oxides of nitrogen, phosphine, arsine, carbon dioxide and watervapour are impurities present in the laboratory.

(b) The impurities can be removed from hydrogen by passing it through

Silver nitrate solution to remove arsine and phosphine.

Lead nitrate solution to remove hydrogen sulphide.

Pb(NO₃)₂ + H₂S → PbS + 2HNO₃

Caustic potash solution to remove sulphur dioxide, carbon dioxide and oxides of nitrogen.

SO₂ + 2KOH → K₂SO₃ + H₂O

CO₂ + 2KOH→ K₂CO₃+ H₂O

2NO₂ + 2KOH →KNO₂ + KNO₃ + H₂O

A drying agent used to dry the gas. Common drying agents such as fused calcium chloride, caustic potash stick and phosphorus pentoxide remove water vapour.

So, the gas is purified and dried and then collected over mercury because mercury does not react with it.

Question 4

Which test should be made before collecting hydrogen in a gas jar?

Answer 4

Test: Collect some amount of gas in a test tube and take it to a flame.

If the gas burns quietly, then there is no more air in the flask.

Question 5

Why nitric acid is not used in the preparation of hydrogen?

Answer 5

Nitric acid is a powerful oxidising agent, and the oxygen formed due to its decomposition oxidiseshydrogen to give water thus defeating the purpose of the reaction.

3Zn + 8HNO₃ → 3Zn(NO₃)₂ + 4H₂O + 2NO

Question 6

Why hot concentrated sulphuric acid is not used in the preparation of hydrogen?

Answer 6

Conc. sulphuric acid is not used in the preparation of hydrogen as it will produce sulphur dioxide.

Zn + 2H₂SO₄ →ZnSO₄ + SO₂ + 2H₂O

Question 7

Hydrogen is manufactured by ‘Bosch Process’.

(a) Give the equations with conditions.

(b) How can you obtain hydrogen from a mixture of hydrogen and carbon monoxide?

Answer 7

(a) C + H₂O→ (CO + H₂) – ∆

(b) (CO + H₂)+ H₂O→CO₂ + 2H₂ + ∆

The mixture is passed through ammoniacal cuprous chloride solution in order to dissolve any uncombined carbon monoxide.

CuCl + CO + 2H₂O →CuCl.CO.2H₂O

Question 8

Give equations to express the reaction between:

(a) Steam and red hot iron

(b) Calcium and water

Answer 8

(a) 3Fe + 4H₂O⇋ Fe₃O₄ + 4H₂

(b) Ca + 2H₂O ⇋ Ca(OH)₂ + H₂

Question 9

A small piece of calcium metal is put into a small trough containing water. There is effervescence and white turbidity is formed.

(a) Name the gas formed in the reaction. How would you test the gas?

(b) Write an equation for the reaction.

Answer 9

Hydrogen gas. When red litmus is introduced in the solution, it turns blue.

(a) Ca + 2H₂O → Ca(OH)₂+ H₂

(b) The solution turns blue.

(c) If dilute hydrochloric acid is added to the turbid solution, then they react and neutralise each other, forming the soluble salt calcium chloride (CaCl₂) and water.

Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂O

Question 10

Thin strips of magnesium,copper and iron are taken.

(a) Write down what happens when these metals are treated as follows:

(i) Heated in presence of air

(ii) Heated with dil.HCl

(iii)Added to an aqueous solution of zinc sulphat

(b) Arrange these metals in descending order of reactivity.

Answer 10

(a)

(i) On heating thin strips of magnesium, copper and iron, they form oxides.

(ii) Magnesium and iron react with HCl liberating hydrogen and forming their respective salts. Hydrogen cannot be prepared from metals which are below it in the activity series of metals (such as copper) because only metals which are more reactive than hydrogen can displace it from acids.

(iii) Only magnesium will displace zinc from zinc sulphate solution because magnesium is more reactive than zinc in the activity series of metals. No reaction takes place in case of copper and iron because they are less reactive than zinc.

(b)Mg > Fe > Cu

Question 11

Choose the correct option:

(a )Hydrogen is evolved by the action of cold dil. HNO₃ on
A. Fe B. Cu C. Mg D. Zn

(b) Which metal absorbs hydrogen?
A. Al B. Fe C. Pd D. K

(c)The composition of nucleus of deuterium is
A. 1 e^– and 1P B. 1 P and 1 A
C. 1 n and 1 e^–D. 2P and 1 e^–

(d) Elements which show unique nature in the preparation of hydrogen are:
A. Na, K, Li B. Mg, Ca, Ba
C. Al, Zn, PbD. Fe, Cu, Ag

Answer 11

(a) C. Mg

(b) C. Pd

(d) C. Al, Zn, Pb

Question 12

Give reasons for the following:

(a) Zinc granules are used in lab preparation of hydrogen.

(b) Purified and dried hydrogen is collected over mercury.

(c)The end of the thistle funnel should be dipped under acid

(d) Dilute sulphuric acid cannot be replaced by concentrated acid in the preparation of hydrogen.

Answer 12

(a) Zinc granules are preferred over pure zinc in the lab preparation of hydrogen because the impurity present in granulated zinc is copper, whose catalysing effect speeds up the rate of the reaction.

(b) Purified and dried hydrogen is collected over mercury because mercury has no reaction with it.

(c) The end of the thistle funnel should be dipped under acid so as to prevent the gas from escaping from the thistle funnel.

(d) Dilute sulphuric acid cannot be replaced by concentrated acid in the preparation of hydrogen because it is a strong oxidising agent and it will produce sulphur dioxide.

Study of First Element-Hydrogen Exercise – 6(C)

Question 1

(a) Where does hydrogen occur in free state?

(b) How did the name ‘hydrogen’ originate?

Answer 1

(a) In the free state, hydrogen is found in traces in the earth’s crust and atmosphere. Volcanic gases contain 0.025%, the earth’s crust 0.98%, the earth’s atmosphere 0.01% and the atmosphere of the Sun and stars 1.1%.

(b) The name ‘hydrogen’ originated on account of its ability to form water.

Question 2

Hydrogen can be prepared with the help of cold water. Give a reaction of hydrogen with:

(a) A monovalent metal

(b) A divalent metal

Answer 2

(a) 2K + 2H₂O →2KOH + H₂

(b) Ca + 2H₂O → Ca(OH)₂ + H₂

Question 3

Which metal is preferred for collecting hydrogen from:

(a) Cold water

(b) Hot water

Answer 3

Metal preferred for collecting hydrogen from

(a) Cold water: Sodium

(b) Hot water: Magnesium

Question 4

Hydrogen may be prepared in the laboratory by the action of a metal on an acid.

(a) Which of the metals copper, zinc, magnesium or sodium would be the most suitable?

(b) Which of the acids dilute sulphuric, concentrated sulphuric, dilute nitric acid and concentrated nitric acid would you choose? Explain why you would not use the acids you reject.

Answer 4

(a) Zinc is the most preferred metal in the laboratory preparation of hydrogen.

(b) Dilute sulphuric acid.

Conc. nitric acid, even in its dilute form, is not used in the preparation of hydrogen from metals because it is a powerful oxidising agent and oxygen formed due to its decomposition oxidiseshydrogen to give water, thus defeating the purpose of the reaction.

Conc. sulphuric acid is not used in the preparation of hydrogen as it will produce sulphur dioxide.

Common drying agents such as fused calcium chloride, caustic potash stick and phosphoruspentoxide remove water vapour.

Question 5

Why are the following metals not used in the lab. preparation of hydrogen?

(a) calcium

(b) iron

(d) sodium

Answer 5

(a) Calcium is expensive.

(b) Iron has to be heated, and hydrogen thus produced contains impurities such as hydrogen sulphide and sulphur dioxide.

(c) Aluminium forms a protective coating of Al₂O₃ due to its great affinity for oxygen. So, it does not give hydrogen with acid after the reaction has occurred for some time.

(d) Sodium reacts violently with acid.

Question 6

Based on the reactions of water on metals, arrange the following metals in increasing order of reactivity: iron, sodium, magnesium, zinc, calcium

Answer 6

Increasing order of reactivity of metals:

Iron < Zinc < Magnesium < Calcium < Sodium

Question 7

Hydrogen is evolved when dilute HCl reacts with magnesium, but nothing happens in the case of mercury and silver. Explain.

Answer 7

Hydrogen is evolved when dilute HCl reacts with magnesium which is placed above hydrogen in the activity series. However, this does not occur for metals below hydrogen such as mercury and silver. This is because only metals which are more reactive than hydrogen can displace it from HCl.

Question 8

Steam can react with metal and non-metal to liberate hydrogen. Give necessary conditions and equations for the same.

Answer 8

With metals:

3Fe + 4H₂O ⇋ Fe₃O₄ + 4H₂

With non-metals:

Steam is passed over hot coke (1000°C) in furnaces of a special design called inverters giving water gas.

C + H₂O (CO + H₂) – ∆

Water is mixed with excess steam and passed over heated ferric oxide which acts as a catalyst and chromic oxide which acts as a promoter.

(CO + H₂) + H₂O CO₂+ 2H₂ + ∆

The above mixture CO₂ + H₂ is formed through cold water under pressure (30 atm) or through caustic potash solution, which dissolves the more soluble carbon dioxide leaving hydrogen.

2KOH + CO₂ →K₂CO₃ + H₂O

The mixture is passed through ammoniacal cuprous chloride solution in order to dissolve any uncombined carbon monoxide.

CuCl + CO + 2H₂O →CuCl.CO.2H₂O

Question 9

Hydrogen is obtained by displacement from:

(a) dilute sulphuric acid

(b) dilute hydrochloric acid

Write equations using zinc and iron.

Why does copper not show similar behavior?

Answer 9

(a) Zn + H₂SO₄ → ZnSO₄ + H₂

(b) Fe + H₂SO₄ → FeSO₄ + H₂

Hydrogen cannot be prepared from metals which are below it in the activity series of metals such as copper because only metals which are more reactive than hydrogen can displace it from acids.

Question 10

Give reason for the following:

(a) Though lead is above hydrogen in the activity series, it does not react with dilute hydrochloric acid or dilute sulphuric acid.

(b) Potassium and sodium are not used for reaction with dilute hydrochloric acid or dilute sulphuric acid in laboratory preparation of hydrogen.

Answer 10

(a) It forms an insoluble coating of lead sulphate or lead chloride. So, further reaction is prevented.

(b) Potassium and sodium react violently with acid. Hence, potassium and sodium are not used for reaction with dilute hydrochloric acid or dilute sulphuric acid in the laboratory preparation of hydrogen.

Question 11

Name two alkalies that can displace hydrogen. Give balanced equations for the same. Why are the metals you have used considered to have unique nature?

Answer 11 two alkalies that can displace hydrogen

NaOH and KOH

Zn + 2NaOH → Na₂ZnO₂ + H₂

Zn + 2KOH → K₂ZnO₂ + H₂

Metals such as zinc, lead and aluminium have a unique nature. They react with acids and can even react with hot alkalis to form hydrogen and a soluble salt.

Question 12

Complete and balance the following reactions.

(a) Na + H₂O →_____________ +___________

(b) Ca + H₂O →_____________ +___________

(d) Zn + H₂O →_____________ +___________

(e) Fe + H₂O →_____________ +___________

(f) Zn + HCl →_____________ +___________

(g) Al + H₂SO₄ →_____________ +___________

(h) Fe + HCl →_____________ +___________

(i) Zn + NaOH →_____________ +___________

(j) Al + KOH + H₂O→_____________ +___________

Answer 12

(a) 2Na + 2H₂O → 2NaOH + H₂

(b) Ca + 2H₂O → Ca(OH)₂ + H₂

(d) Zn + H₂O → ZnO + H₂

(e) 3Fe + 4H₂O ⇋Fe₃O₄ + 4H₂

(f) Zn + 2HCl → ZnCl₂ + H₂

(g) 2Al + 3H₂SO₄ →Al₂(SO₄)₃ + 3H₂

(h) Fe +2HCl →FeCl₂ + H₂

(i) Zn + 2NaOH → Na₂ZnO₂ + H₂

(j) 2Al + 2KOH + 2H₂O →2KAlO₂ + 3H₂

Question 13

If the following are kept in closed vessels at over 400°C, what would happen to them?

(a) iron filing and steam

(b) hydrogen and magnetic oxide of iron?

Answer 13

(a) Iron oxide is formed with the evolution of hydrogen gas.

(b) Hydrogen reduces heated magnetic oxide of iron.

Question 14

(a) A metal in the powdered from reacts very slowly with boiling water, but it decomposes in steam. Name the metal.

(b) Write a balanced equation for the reaction occurring in (a).

Answer 14

(a) Magnesium

(b) (i) Mg + 2H₂O → Mg(OH)₂ + H₂

(i) Mg + H₂O →MgO + H₂

Question 15

What do you observe when hydrogen gas is passed through a soap solution?

Answer 15

On passing hydrogen gas through soap solution, soap bubbles filled with hydrogen fly high and burst. This behavior proves that hydrogen is lighter than air.

Question 16

Under what conditions can hydrogen be made to combine with?

(a) nitrogen?

(b) chlorine?

(d) oxygen?

Name the products in each case and write the equation for each reaction.

Answer 16

(a) Three volumes of hydrogen and one volume of nitrogen react at temperature 450-500°C and pressure 200-900 atm in the presence of finely divided iron catalyst with molybdenum as promoter to give ammonia.

N₂ + 3H₂⇋ 2NH₃

(b) Equal volumes of hydrogen and chlorine react slowly in diffused sunlight to form hydrogen chloride.

H₂ + Cl₂ →2HCl

H₂ + S → H₂S

(d) Hydrogen burns in the presence of electric spark with a ‘pop’ sound in oxygen and with a blue flame forming water.

2H₂ + O₂ →2H₂O

Question 17

When hydrogen is passed over a black solid compound A, the products are a ‘colourless liquid’ and a ‘reddish brown metal B’.

Substance B is divided into two parts each placed in separate test tubes.

Dilute HCl is added to one part of substance B and dilute HNO₃ to the other.

(a) Name the substances A and B.

(b) Give two tests for the colourless liquid formed in the experiment.

(d) Write an equation for the reaction between hydrogen and substance A.

(e) Is there any reaction between substance B and dilute hydrochloric acid? Give reasons for your answer.

Answer 17

(a) A = CuO, B = Cu

(b) Blue and red litmus paper when dipped in the colourless liquid do not change colour. This confirms the liquid formed is neutral and is water.

It changes white anhydrous copper sulphate to blue salt.

(c) Black copper oxide (A) on heating with hydrogen reduces copper oxide to reddish brown copper and itself gets oxidised to water.

Hydrogen is a strong reducing agent and removes oxygen from less active metals, i.e. it removes oxygen from heated metal oxides when passed over them and itself gets oxidised to water.

(d) CuO + H₂ Cu + H₂O

Cu + HCl →No reaction

(e) Copper is less reactive than hydrogen and hence cannot displace it from HCl.

Exercise – 6(D) Chapter-6

Question 1

Describe briefly the ionic concept of oxidation and reduction. Give an equation to illustrate.

Answer 1

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

Zn → Zn²⁺ + 2e^–

Oxidation is also defined as a chemical process which involves

Addition of oxygen

Addition of electronegative ion

Removal of hydrogen

Removal of electropositive ion (element)

In the electronic concept, reduction is a process in which an atom or ion gains electrons.

Cu²⁺ + 2e^–→ Cu

Reduction is also defined as a chemical process which involves

Removal of oxygen

Addition of electropositive ion

Addition of hydrogen

Removal of electronegative ion

Question 2

Is it essential that oxidation and reduction must occur side by side in a chemical reaction? Explain

Answer 2

In a chemical reaction, if one substance is oxidised, the other substance must necessarily be reduced. This is because the electrons lost during oxidation are simultaneously gained during reduction and vice versa.

For example: Zinc reacts with copper sulphate to form zinc sulphate and copper.

CuSO₄ + Zn → ZnSO₄+ Cu

Cu + 2SO₄^2-+ Zn →Zn + 2SO₄^2- + Cu

Writing the half reaction,

Zn → Zn²⁺+ 2e^– (Oxidation)

Cu²⁺ + 2e^–→ Cu (Reduction)

They occur simultaneously as

Cu²⁺ + Zn→ Zn²⁺+ Cu

Thus, oxidation and reduction always occur simultaneously.

Question 3

State, giving reasons, whether the substances printed in bold letters have been oxidized or reduced.

(a) PbO + CO → Pb + CO₂

(b) Mg + 2HCl → MgCl₂ + H₂

(c) H₂S + Cl₂→ 2HCl + S

(d) Cl₂ + H₂S → 2HCl + S

Answer 3

(a) PbO in the given reaction is reduced to Pb by losing oxygen.

(b) Magnesium undergoes oxidation by loss of electrons (Mg – 2e^–→ Mg²⁺).

(d) Chlorine undergoes reduction by the addition of hydrogen to form HCl.

Question 4

State whether the following conversions are oxidation or reduction:

(a) PbO₂ + SO₂→ PbSO₄

(b) Cu²⁺+ 2 e^–→ Cu

(d) 2Cl^– – e^–→ Cl₂

Answer 4

(a) Oxidation

(b) Reduction

(d) Oxidation

Question 5

In the following reaction: A⁺ + B → A + B⁺. Write half reactions for this reaction and name:

(a) oxidizing agent

(b) substance oxidized

Answer 5

Half reaction:

A⁺ + e^–→ A (Reduction)

B → B + e^–(Oxidation)

(a) A

(b) B

Question 6

Divide the following reactions into oxidation and reduction half reactions:

(i) Zn + Pb²⁺→ Pb + Zn²⁺

(ii) Zn + Cu²⁺ → Cu + Zn²⁺

(iii) Cl₂ + 2Br^– → Br₂ + 2Cl^–

Answer 6

(i) Zn + Pb²⁺ → Pb + Zn^{2+

Zn → Zn 2+ + 2 e- —- Oxidation

Pb2+ + 2 e → Pb —- Reduction}

(ii) Zn + Cu²⁺ → Cu + Zn^{2+

Zn → Zn 2+ + 2 e- —- Oxidation

Cu2+ + 2 e → Cu —- Reduction}

(iii) Cl₂ + 2Br^– → Br₂ + 2Cl^–
Cl₂→ 2Cl^– + 2 e^– —- Oxidation
2Br^‒ + 2 e → Br₂—- Reduction

Question 7

(a) Write the equation in the ionic form

CuSO_4(aq)+ Fe_(s)→ FeSO_4(aq) + Cu_(s)

(b) Divide the above equation into oxidation and reduction half reactions.

Answer 7

(a) Equation in the ionic form:

Cu²⁺ SO₄^2- + Fe → Fe²⁺SO₄^2- + Cu

(b) Fe → Fe²⁺2 e^– —- Oxidation

Cu²⁺+ 2 e → Cu —- Reduction

Question 8

Give reasons:

(a) Hydrogen is collected by the downward displacement of water and not of air, even though it is lighter than air.

(b) A candle brought near the mouth of a jar containing hydrogen gas starts burning but is extinguished when pushed inside the jar.

Answer 8

(a) Hydrogen is collected by the downward displacement of air because
i. It is insoluble in water.
ii. It forms an explosive mixture with air and therefore cannot be collected by the downward displacement of air even though it is lighter than it.

(b) Hydrogen is combustible, but it does not support combustion. So, the candle burns in air or oxygen when brought near the mouth of a jar containing hydrogen but is extinguished when pushed inside the jar as the supply of oxygen is cut off.

(c) Apparatus for laboratory preparation of hydrogen should be airtight and away from a naked flame because a mixture of hydrogen and air explodes violently when brought near a flame.

Question 9

Select the odd one out and justify your answer.

(a) Zn, Fe, Mg and Na

(b) SO₂, H₂S, NH₃ and CO₃

(d) Fe, Pb, Al and Zn

Answer 9

(a) Na

The other metals react with dil. HCl liberating hydrogen gas, while sodium reacts violently with acid.

(b) NH₃ is basic in nature.

Metals more reactive than hydrogen can displace it from acids.

(d) Pb

Lead reacts with dilute sulphuric acid or HCl and forms an insoluble coating of lead sulphate or lead chloride.

The others react with dilute sulphuric acid or HCl to liberate hydrogen.

Question 10

(a) Helium is preferred to hydrogen for filling balloons because it is:

(i) lighter than air

(ii) almost as light as hydrogen

(iii) non-combustible

(iv) inflammable

(b) Reacting with water, an active metal produces

(i) oxygen

(ii) nitric acid

(iii) a base

(iv) none of these

(c) A metal oxide that is reduced by hydrogen is

(i) Al₂O₃

(ii)CuO

(iii) CaO

(iv) Na₂O

(d) Which of the following statements about hydrogen is incorrect?

(i) It is an inflammable gas

(ii) It is the lightest gas.

(iii)It is not easily liquefied

(iv )It is a strong oxidizing agent.

(e) For the reaction PbO + H₂→ Pb + H₂O, which of the following statements is wrong?

(i) H₂ is the reducing agent.

(ii) PbO is the oxidizing agent.

(iii) PbO is oxidized to Pb.

(iv) H₂ is oxidized to H₂O.

(f) Which metal gives hydrogen with all of the following: water, acids, alkalis?

(i) Fe

(ii) Zn

(iii) Mg

(iv) Pb

(g) Which of the following metals does not give hydrogen with acids?

(i) Iron

(ii) Copper

(iii) Lead

(iv) Zinc

Answer 10

(a) (iii) non-combustible

(b) (iii) base

(d) (iv) It is a strong oxidising agent.

(e) (iii) PbO is oxidised to Pb.

(f) (ii) Zn

(g) (ii) Cu

Question 11

Choose terms from the options given in brackets to complete these sentences.

(a) When CuO reacts with hydrogen,………………… is reduced and ……………….is oxidized to ………………… . (CuO, H₂,Cu,H₂O)

(b )Hydrogen is ………………… soluble in water. (sparingly, highly, moderately)

(iron, magnesium, aluminium, sodium , calcium)

(d) Sodium ………………. reacts smoothly with cold water. (metal, amalgam, in the molten state)

(e) A metal …………….. hydrogen in the activity series gives hydrogen with …………… acid or … ………… acid.

(above, below, dilute hydrochloric, concentrated hydrochloric, dilute sulphuric).

Answer 11

(a) CuO, H₂, H₂O

(b) sparingly

(d) amalgam

(e) above, dilute hydrochloric, dilute sulphuric acid

Question 12

Correct the following statements:

(a) Hydrogen is separated from CO by passing the mixture through caustic potash solution.

(b) All metals react with acids to give hydrogen.

(d) Very dilute nitric acid reacts with iron to produce hydrogen.

(e) Conc. H₂SO₄ reacts with zinc to liberate hydrogen.

Answer 12

(a) Hydrogen is separated from CO by passing the mixture through caustic potash solution.

(b) All metals above hydrogen in the activity series react with acids to give hydrogen.

(d) Very dilute nitric acid reacts with magnesium and manganese to produce hydrogen.

(e) Dil. H₂SO₄ reacts with zinc to liberate hydrogen.

Question 13

Name:

(a) an oxidizing agent that does not contain oxygen.

(b) a substance that oxidizes concentrated HCl to chlorine.

(d) a liquid that is an oxidizing agent as well as a reducing agent.

(e) a gas that is an oxidizing as well as a reducing agent.

(f) a solid that is an oxidizing agent.

Answer 13

(a) Chlorine

(b) MnO₂

(d) Hydrogen peroxide

(e) MnO₂

Class 9 Chemistry Water

Question 1

Water exists in all three states. Discuss.

Answer 1

In the Free State, water occurs in the solid, liquid and gaseous states.

(a)Solid state: A large amount of fresh water is found in the form of snow or ice.

(b)Liquid state: Most of the water present in oceans and found in streams, rivers, lakes, ponds and springs on land is water in the liquid state.

(c)Gaseous state: Water vapour present in the air is in the gaseous state. Water vapour condenses in the sky to form clouds. Mist and fog are also examples of water in the gaseous form.

Question 2

Why water is considered a compound?

Answer 2

Water is considered a compound because it is made of two elements hydrogen and oxygen combined in the ratio 1:8 by mass.

Components of water cannot be separated by physical methods but can be separated by electrolysis of water.

Question 3

(a)Why does temperature in Mumbai and Chennai not fall as low as it does in Delhi?

(b)Give the properties of water responsible for controlling the temperature of our body.

Answer 3

a)The temperature in Mumbai and Chennai do not fall as low as in Delhi because these cities are situated in the coastal areas. Due to high specific heat capacity, the presence of a large amount of water is able to modify the climate of the nearby land areas making them warmer in winter and cooler in summer. So, the temperature does not fall as low as it does in Delhi.

b) Our body is almost 65% of water, and it has the property of specific heat. Due to high specific heat capacity, the presence of a large amount of water is able to modify the climate of the body and control the temperature of our body, which is warm in winter and cool in summer.

Question 4

‘Water is the universal solvent’. Comment.

Answer 4

Water dissolves many substances forming an aqueous Solution. It can dissolve solids, liquids and gases. When a solid dissolves in water, the solid is the solute, the water is the solvent and the resultant liquid is the Solution. So, it is said that water is a universal solvent. In other words, water can dissolve nearly every substance.

Question 5

What causes the violence associated with torrential rain?

Answer 5

The sudden release of the latent heat of condensation causes the violence associated with torrential rain.

Question 6

(a)Which property of water enables it to modify the climate?

(b)Density of water varies with temperature. What are its consequences?

(c)What is the effect of impurities present in the water on the melting point and boiling point of water?

Answer 6

(a)Due to the high specific heat capacity, the presence of a large amount of water is able to modify the climate.

(b)The property of anomalous expansion of water enables marine life to exist in the colder regions of the world, because even when water freezes on the top, it is still liquid below the ice layer, as the density of water is greater than that of ice.

(c)The boiling point of water increases due to the presence of dissolved impurities.

The freezing point of water decreases due to the presence of dissolved impurities.

Question 7

How do fishes and aquatic animals survive when the pond gets covered with thick ice?

Answer 7

Water has an unusual physical property. When cooled, it first contracts in volume, as do other liquids, but at 4°C (maximum density), it starts expanding, and continues to do so till the temperature reaches 0°C, the point at which it freezes into ice.

Question 8

The properties of water are different from the properties of the elements of which it is formed. Discuss.

Answer 8

Properties of water are different from the properties of elements from which it is formed.
Property	Water	Elements – Oxygen and Hydrogen
Nature	It is a clear, colourless, odourless, tasteless and transparent liquid.	These are colourless, odourless, tasteless and non-poisonous gases.
Solubility	It can dissolve many substances and is called a universal solvent.	Oxygen and hydrogen are slightly soluble in water.
Density	Pure water has maximum density at 4°C.	Oxygen is heavier than air, and hydrogen is the lightest of all the known gases.

Question 9

How is aquatic life benefited by the fact that water has maximum density at 4^oC?

Answer 9

The property of anomalous expansion of water enables aquatic life to exist because water freezes on the surface of the water body, but it is still liquid below the ice layer.

Question 10

What are the observations and conclusions when tap water is boiled and evaporated in a water glass?

Answer 10

When tap water is boiled and evaporated:

Observations:

(a) A number of concentric rings of solid matter are seen on the watch glass after evaporation of tap water.

Conclusion:

(b) Tap water contains dissolved salts, minerals and impurities.

Question 11

What is the importance of dissolved salts in water?

Answer 11

Importance of dissolved salts in water:

(a)Dissolved salts provide specific taste to water.

(b)Dissolved salts act as micronutrients for the growth and development of living beings.

Question 12

State the importance of the suitability of CO₂ and O₂ in water.

Answer 12

They add taste to water for drinking purposes.

Question 13

How is air dissolved in water different from ordinary air?

Answer 13

Oxygen is more soluble in water than nitrogen. Air dissolved in water contains a higher percentage of oxygen (30-35%). Oxygen is only 21% in ordinary air. In this way, air dissolved in water is different from ordinary air.

Question 14

Identify A, B, C, and D first one is done for you.

Answer 14

When a solid changes into a liquid, it absorbs heat equal to the latent heat of fusion. When a liquid changes into a solid, it loses heat equal to the latent heat of solidification.

a liquid changes into a gas, it absorbs heat equal to the latent heat of vaporisation. When a gas condenses into a liquid, it loses heat equal to the latent heat of condensation.

Question 15

Explain why:

(a)Boiled or distilled water tastes flat.

(b)Ice at zero degrees centigrade has greater cooling effect than water at 0^oC.

(c)Burns caused by steam are more severe than burns caused by boiling water.

(d)Rivers and lakes do not freeze easily?

(e)Air dissolved in water contains a higher proportion of oxygen.

(f)If distilled water is kept in a sealed bottle for a long time, it leaves etchings on the surface of the glass.

(g)Rain water does not leave behind concentric rings when boiled.

Answer 15

(a)Boiled water tastes flat because it does not contain dissolved matter such as air, carbon dioxide and other minerals.

(b)Ice at 0°C gives more cooling effect than water at 0°C because at 0°C ice absorbs 336 J per gram of energy to melt to 0°C water.

(c)Burns caused by steam are more severe than burns caused by boiling water because of high specific latent heat of condensation. 2268 J/g of heat is released when 1 g of steam condenses to form 1 gm of water.

(d)Due to the high specific latent heat of solidification of water, rivers and lakes do not freeze easily.

(e)Air dissolved in water contains a higher percentage of oxygen because the solubility of oxygen in water is more than that of oxygen in air.

(f)If distilled water is kept in a sealed bottle for a long time, it etches the surface of glass because substances which are apparently insoluble in water actually dissolve in minute traces in water.

(g)Rain water does not leave concentric rings when boiled because rain water does not contain dissolved solids.

Exercise – 3(B)

Question 1 Explain the terms:

(Answer 1

(a)Solution: A Solution is a homogeneous mixture of two or more substances, the components of which cannot be seen separately.

(b)Solute: A solute is the substance which dissolves in a solvent to form a Solution.

(c)Solvent: A solvent is the medium in which a solute dissolves.

Solution = Solute + Solvent

Question 2

Explain why a hot saturated Solution of potassium nitrate forms crystals as it cools.

Answer 2

Solubility of nitrates decreases with a fall in temperature. Thus, when a hot saturated Solution of potassium nitrate cools, it forms crystals as it separates from the Solution.

Question 3

Give three factors which affect the solubility of a solid solute in a solvent.

Answer 3

Three factors on which the solubility of a solid depend:

(i)Temperature

(ii)Nature of the solid

(iii)Nature of the solvent

Question 4

(a) If you are given some copper sulphate crystals, how would you proceed to prepare its saturated Solution at room temperature?

(b) How can you show that your Solution is really saturated?

Answer 4

(a)Take 100 g of distilled water in a beaker. Add to this one gram of copper sulphate crystals.

(b) This mixture with the help of a glass rod and dissolve the copper sulphate crystals. Similarly, go on dissolving more copper sulphate (1 gram at a time) with constant and vigorous stirring. A stage is reached when no more copper sulphate dissolves. It is called a saturated Solution at this temperature.

Question 5

(a)Define (i) Henry’s law and (ii) Crystallisation (iii) Seeding.

(b)State the different methods of crystallisation.

Answer 5

(a)

(I) Henry’s law:

At any given temperature, the mass of a gas dissolved in a fixed volume of a liquid or Solution is directly proportional to the pressure on the surface of a liquid.

(ii) Crystallisation:

It is the process by which crystals of a substance separate out on cooling its hot saturated Solution.

(iii) Seeding:

This process of inducting crystallisation by adding a crystal of pure substance into saturated solution is called seeding.

(b)

In the laboratory, crystals may be obtained by the following methods:

(i)By cooling a hot saturated Solution gently

(ii)By cooling a fused mass

(iii)By sublimation

(iv)By slowly evaporating a saturated Solution

Question 6

What would you observe when crystals of copper (II) sulphate and iron (II) sulphate are separately heated in two test tubes strongly?

Answer 6

Action of heat on copper (II) sulphate crystals

When copper (II) sulphate crystals are heated in a hard glass test tube, the following observations are observed:

(i)The crystals are converted to a powdery substance.

(ii)The crystals lose their blue coloration on further heating.

(iii)Steaming vapors are produced inside the tube which condense near the mouth of the tube to form a colorless liquid.

(iv)On further heating, steam escapes from the mouth of the tube and water gets collected in a beaker placed under the mouth of the tube.

(v)On further heating, the residue changes to a white powder and steam stops coming out.

CuSO₄.5H₂O → CuSO₄ + 5H₂O

Action of heat on iron (II) sulphate

When iron (II) sulphate is heated in a test tube, the following is observed:

(i)The crystals crumble to a white powder and a large amount of steam and gas are given out.

(ii)On strong heating, a brown residue of ferric oxide (Fe₂O₃) is produced and a mixture of SO₂ and SO₃ is given off.

Question 7

Give the names and formulae of two substances in each case:

(a)Hydrated substance

(b)Anhydrous substance

(c)Liquid drying agent

(d)A basic drying agent

Answer 7

(a) (i) Washing soda crystals: Na₂CO₃.10H₂O

(ii) Blue vitriol: CuSO₄.5 H₂O

(b) (i) Table salt: NaCl

(ii) Nitre: KNO₃

(c)Sulphuric acid: H₂SO₄

(d)Quick lime: CaO

Question 8

What is the effect of temperature on solubility of KNO₃ and CaSO₄ in water?

Answer 8

Solubility of potassium nitrate (KNO₃) in water increases with an increase in temperature.

Solubility of calcium sulphate (CaSO₄) in water decreases with an increase in temperature.

Question 9

Solubility of NaCl at 40^oC is 36.5 g. What is meant by this statement?

Answer 9

Solubility of NaCl at 40°C is 36.5 g means that 36.5 g of NaCl dissolves in 100 g of water at a temperature of 40°C.

Question 10

Which test will you carry out to find out if a given Solution is saturated or unsaturated or supersaturated?

Answer 10

A Solution in which more of a solute can be dissolved at a given temperature is an unsaturated Solution.

The Solution in which no more solute can be dissolved at a given temperature is a saturated Solution at that temperature.

Solution in which some solute separates on cooling slightly is a super saturated Solution.

Question 11

What is the effect of pressure on solubility of gases? Explain with an example.

Answer 11

With an increase in pressure, the solubility of a gas in water increases.

With an increase in temperature, the solubility of a gas in water decreases.

For example, the solubility of carbon dioxide in water under normal atmospheric pressure is low, but when the water surface is subjected to higher pressure, a lot more of CO₂ gas gets dissolved in it.

Similarly, in case of soda water, on opening the bottle, the dissolved gas rapidly bubbles out because the pressure on the surface of the water suddenly decreases.

Question 12

State the term:

(a)A Solution where solvent is a liquid other than water.

(b)When a substance absorbs moisture on exposure to moist air and dissolves in the absorbed water and turned to Solution.

(c)A substance which contains water of crystallisation.

(d)When a substance absorbs moisture from the atmosphere but does not form a Solution.

(e)When a compound loses its water of crystallisation on exposure to dry air.

(f)The substance that can remove hydrogen and oxygen atoms in the ratio of 2:1(in the form of water) from the compound.

Answer 12 Water

(a)Non-aqueous Solution

(b)Deliquescence

(c)Hydrated substance

(d)Hygroscope

(e)Efflorescence

(f)Dehydrating agent

Question 13

Explain why:

(a)Water is an excellent liquid to use in cooling systems.

(b)A Solution is always clear and transparent.

(c)Lakes and rivers do not suddenly freeze in the winters.

(d)The solute cannot be separated from a Solution by filtration.

(e)Fused CaCl₂ or conc. H₂SO₄ is used in a desiccator.

(f)Effervescence is seen on opening a bottle of soda water.

(g)Table salts become sticky on exposure to humid air during the rainy season.

Answer 13

(a)Water is an excellent liquid to use in cooling systems because of its high specific heat.

(b)A water-soluble solid disappears in a Solution where the solvent is water, and water has the property of being clear and transparent. So, the Solution is also clear and transparent.

(c) Lakes and rivers do not freeze suddenly in winters

because of the high specific latent heat of solidification, i.e. the amount of heat released when 1 g of water solidifies to form 1 g of ice at 0°C. It is about 336 J/g or 80 cal/g.

(d)The component which dissolves in a solvent is known as a solute. So, it cannot be separated from a Solution by filtration. However, filtration is used when the solute is insoluble in the Solution.

(e)Fused CaCl₂ or concentrated H₂SO₄ is deliquescent in nature, i.e. it absorbs moisture, and hence, these are used in desiccators as drying agents.

(f)Carbon dioxide is dissolved in soda water under pressure. On opening the bottle, the pressure on the surface of water suddenly decreases; therefore, the solubility of CO₂ in water decreases and the gas rapidly bubbles out.

(g)Table salt becomes sticky on exposure during the rainy season, because it generally contains a small percentage of magnesium chloride and calcium chloride as impurities. These impurities absorb moisture from the monsoon air due to their deliquescent nature, and thus, table salt become sticky.

Question 14 Water

Name a substance whose solubility:

(a)Increases rapidly with temperature.

(b) solubility Increases gradually with temperature.

(d) Initially increases then decreases with rise in temperature.

Answer 14

(a)Potassium nitrate

(b)Potassium chloride

(c)Sodium chloride

(d)Calcium sulphate

Question 15

What are drying or desiccating agents? Give examples.

Answer 15

These are substances which can readily absorb moisture from other substances without chemically reacting with them.

Examples:

Phosphorous pentoxide (P₂O₅), quick lime (CaO)

Answer 16

Common Name	Chemical Name	Formula	Acid, base or salt	Efflorescent, hygroscopic or deliquescent substance
Solid caustic potash	Potassium hydroxide	KOH	Base	Deliquescent substance
Quick lime	Calcium oxide	CaO	Base	Hygroscopic substance
Oil of vitriol	Sulphuric acid	H₂SO₄	Acid	Hygroscopic substance
Washing soda	Hydrated sodium carbonate	Na₂CO₃.10H₂O	Salt	Efflorescent substance
Solid caustic soda	Sodium hydroxide	NaOH	Base	Deliquescent substance
Blue vitriol	Copper sulphate	CuSO₄	Salt	Efflorescent substance

Question 17 Water Selina Solutions Chapter-3

In which of the following substances will there be

(a)Increase in mass

(b)Decrease in mass

(c)No change in mass when they are exposed to air?

Sodium chloride

Iron

Conc. sulphuric acid

Table salt

Sodium carbonate crystals

Answer 17

(a)Increase in mass: Iron and conc. sulphuric acid

(b)Decrease in mass: Sodium carbonate crystals

(c)No change in mass: Sodium chloride

Question 18

State the methods by which hydrated salts can be made anhydrous.

Answer 18

Hydrated salts can be converted to anhydrous substances by heating and also when exposed to dry air.

Example:

Gaber’s salt becomes powdery anhydrous sodium sulphate when exposed to dry air.

Exercise – 3(C

Question 1

What is the composition of water? In what volume its elements combine?

Answer 1

The composition of water is 2 atoms of hydrogen with 1 atom of oxygen (H₂O).

By number of atoms, they combine in the ratio 2:1.

Question 2

What is the use of solubility of oxygen and carbon dioxide in water?

Answer 2 Water Selina Solutions Chapter-3

Air dissolved in water is biologically very important.

Oxygen dissolved in water is used by marine life like fish for respiration, and thus, marine life is sustained.

Aquatic plants make use of dissolved carbon dioxide in photosynthesis to prepare food.

Carbon dioxide dissolved in water reacts with calcium carbonate to form calcium bicarbonate.

Marine organisms such as oysters and snails extract calcium carbonate from calcium bicarbonate to build their shells.

Question 3

Hot saturated Solution of sodium nitrate forms crystals as it cools. Why?

Answer 3

Solubility of sodium nitrate decreases with a fall in temperature. Thus, when a hot saturated Solution of sodium nitrate cools, it forms crystals as it separates from the Solution.

Question 4

What are hydrous substances? Explain with examples.

Answer 4

Substances which contain water molecules along with salt are hydrated substances.

Examples: Sodium carbonate dehydrate: Na₂CO₃.10H₂O

Copper sulphate pentahydrate: CuSO₄.5H₂O

Question 5

Name three methods [CM1] by which hydrous substances can be made anhydrous.

Answer 5

Methods by which hydrous substances can be made anhydrous:

By heating and by Exposure to dry air

Question 6

What is the importance of dissolved impurities in water?

Answer 6

The dissolved impurities in water are salts and minerals.

Dissolved salts provide specific taste to water.

Salts and minerals are essential for growth and development.

They supply the essential minerals needed by our body.

Question 7 Water

State two ways by which a saturated Solution can be changed to unsaturated Solution.

Answer 7

On heating, a saturated Solution becomes unsaturated and more solute can be dissolved in the Solution.

By adding more solvent, a saturated Solution can be made unsaturated.

Question 8

What do you understand by?

(a)Soft water

(b)Hard water

(c)Temporary hard water

(d)Permanent hard water

Answer 8

(a)Water is said to be soft when the water containing sodium salts easily gives lather with soap.

(b)Water is said to be hard when it does not readily form lather with soap.

(c)Water which contains only hydrogen carbonates of calcium and magnesium is called temporary hard water.

(d)Water containing sulphates and chlorides of magnesium and calcium is called permanent hard water.

Question 9

What are the causes for?

(a)Temporary hardness

(b)Permanent hardness

Answer 9

(a)The presence of hydrogen carbonates of calcium and magnesium makes water temporarily hard.

(b)The presence of sulphates and chlorides of magnesium and calcium makes water permanently hard.

Question 10 Water

What are the advantages of (i) soft water and (ii) hard water?

Answer 10

Advantages of soft water:

1) When the water is soft, you use much less soap and fewer cleaning products. Your budget will reflect your savings.

2)Plumbing will last longer. Soft water is low in mineral content and therefore does not leave deposits in the pipes.

3)Clothes last longer and remain bright longer if they are washed in soft water.

Advantages of hard water:

1) Water free from dissolved salts has a very flat taste. The presence of salts in hard water makes it tasty. So, hard water is used in making beverages and wines.

2) Calcium and magnesium salts present in small amounts in hard water are essential for bone and teeth development.

3) Hard water checks the poisoning of water by lead pipes. When these pipes are used for carrying water, some lead salts dissolve in water to make it poisonous. Calcium sulphate present in hard water forms insoluble lead sulphate in the form of a layer inside the lead pipe and this checks lead poisoning.

Question 11

What are stalagmites and stalactites? How are they formed?

Answer 11

In some limestone caves, conical pillar-like objects hang from the roof and some rise from the floor. These are formed by water containing dissolved calcium hydrogen carbonate continuously dropping from the cracks in the rocks. Release of pressure results in the conversion of some hydrogen carbonate to calcium carbonate.

Ca (HCO₃)₂ → CaCO₃ + CO₂ + H₂O

This calcium carbonate little by little and slowly deposit on both roof and floor of the cave.

The conical pillar which grows downwards from the roof is called stalactite and the one which grows upward from the floor of the cave is called stalagmite.

These meet after a time. In a year, some grow less than even a centimetre, but some may be as tall as 100 cm.

CaCO₃ + CO₂ + H₂O → Ca (HCO₃)₂

MgCO₃ + CO₂ + H₂O → Mg (HCO₃)₂

If the water flows over beds of gypsum (CaSO₄.2H₂O), a little bit of gypsum gets dissolved in water and makes it hard.

Question 12 Water Selina Solutions Chapter-3

Name the substance which makes water (i) temporarily hard and (ii) permanently hard.

Answer 12

(i)Hydrogen carbonates of calcium and magnesium

(ii)Sulphates and chlorides of magnesium and calcium

Question 13

Give equations to show what happens when temporary hard water is

(a)Boiled

(b)Treated with slaked lime

Answer 13

(a) when boiled

Ca (HCO₃)₂ → CaCO₃ + H₂O + CO₂↑

Mg (HCO₃)₂ → MgCO₃ + H₂O + CO₂↑

(b) when Treated with slaked lime

Ca(HCO₃)₂+ Ca(OH)₂ → 2CaCO₃ + 2H₂O

Mg (HCO₃)₂+ Ca(OH)_2→ MgCO₃ + 2H₂O

Question 14

State the disadvantages of using hard water.

Answer 14 disadvantages of using hard water.

It is more difficult to form lather with soap.

Scum may form in a reaction with soap, wasting the soap.

Carbonates of calcium and magnesium form inside kettles. This wastes energy whenever you boil a kettle.

Hot water pipes ‘fur up’. Carbonates of calcium and magnesium start to coat the inside of pipes which can eventually get blocked.

Question 15

What is soap? For what is it used?

Answer 15

Soap is chemically a sodium salt of stearic acid (an organic acid with the formula C₁₇H₃₅COOH) and has the formula C₁₇H₃₅COONa.

Soap is used for washing purposes.

Question 16

What is the advantage of a detergent over soap?

Answer 16

Detergents are more soluble in water than soap and are unaffected by the hardness of water as their calcium salts are soluble in water.

Question 17

Why does the hardness of water render it unfit for use in a (i) boiler and (ii) for washing purposes.

Answer 17

Steam is usually made in boilers which are made of a number of narrow copper tubes surrounded by fire. As the cold water enters these tubes, it is immediately changed into steam, while the dissolved solids incapable of changing into vapour deposit on the inner walls of the tubes.

This goes on and makes the bore of the tubes narrower. The result is that less water flows through the tubes at one time and less steam is produced. When the bore of the tube becomes very narrow, the pressure of the steam increases so much that at times the boiler bursts.

If hard water is used,

calcium and magnesium ions of the water combine with the negative ions of the soap to form a slimy precipitate of insoluble calcium and magnesium usually called soap curd (scum).

Formation of soap curd will go on as long as calcium and magnesium ions are present. Till then, no soap lather will be formed and cleaning of clothes or body will not be possible. Moreover, these precipitates are difficult to wash from fabrics and sometimes form rusty spots if iron salts are present in water.

Question 18

Explain with equation, what is noticed when permanent hard water is treated with

(a)Slaked time

(b)Washing soda

Answer 18

(a) Slaked lime

Ca (HCO₃)₂ + Ca(OH)₂ 2CaCO₃ + 2H₂O

Mg (HCO₃)₂+ Ca(OH)₂MgCO₃ + CaCO₃+ 2H₂O

Lime is first thoroughly mixed with water in a tank and then fed into another tank containing hard water. Revolving paddles thoroughly mix the two Solutions. Most of the calcium carbonate settles down. If there is any solid left over, it is removed by a filter. This is known as Clarke’s process.

(b) Washing soda

When washing soda or soda ash is added to hard water, the corresponding insoluble carbonates settle down and can be removed by filtration.

Ca (HCO₃)₂ + Na₂CO₃ CaCO₃ + 2NaHCO₃

Mg (HCO₃)₂+ Na₂CO₃ MgCO₃ + 2NaHCO₃

Question 19

Explain the permit method, how can it be used for softening hard water.

Answer 19

Permit is an artificial zeolite. Chemically, it is hydrated sodium aluminium or tho silicate with the formula Na₂Al₂Si₂O₈.XH₂O. For the sake of convenience, let us give it the formula Na₂P.

A tall cylinder is loosely fille with lumps of permit. When hard water containing calcium and magnesium ions percolates through these lumps, ions exchange. Sodium permit is slowly changed into calcium and magnesium permit, and the water becomes soft with the removal of calcium and magnesium ions.

When no longer active, permit is regenerated by running a concentrated Solution of brine over it and removing calcium chloride formed by repeated washing.

CaP + 2NaCl → Na₂P + CaI₂

Chemical Changes and Reactions

Question 1

(a) What is a chemical reaction?

(b) State the conditions necessary for a chemical change or reaction.

Answer 1

(a) A chemical reaction is the process of breaking the chemical bonds of the reacting substances (reactants) and making new bonds to form new substances (products).

(b) Conditions necessary for a chemical change or reaction are

(i) Evolution of gas

(ii) Change of colour

(iii) Formation of precipitate

(iv)Change of state

Question 2

Define the following terms

(a). Chemical bond

(b). Effervescence

(c). Precipitate

Answer 2

(a). A chemical bond is the force which holds the atoms of a molecule together as in a

compound.

(b). Formation of gas bubbles in a liquid during a reaction is called effervescence.

(c). Chemical reactions which are characterised by the formation of insoluble solid substances are called precipitates.

Question 3

Give an example of a reaction where the following are involved

(a) Heat

(b) Light

(d) Close contact

(e) Solution

(f) Pressure

(g) Catalyst

Answer 3

Question 4

Define

(a) Photochemical reaction (b) Electrochemical reaction Give an example in each case.

Answer4

(a) It is a reaction which occurs with absorption of light energy.

(b) It is a reaction which occurs with absorption of electrical energy.

Question 5

Give an example of each of the following chemical changes:

(a) A photochemical reaction involving

(i) Silver salt (ii) water

(b)A reaction involving

(i) Blue Answer

(ii) Formation of dirty green precipitate

(c)Two gases combine to form white solid

(d)Two solids combine to form a liquid

(e)A reaction where colour change is noticed

REFER THE BOOK CHAPTER OF NOTES PROVIDED

Question 6

Write the chemical reaction where the following changes are observed.

(a) Gas is evolved

(b) Colour change is noticed (c) Precipitate is formed

(d) Physical state is changed

Answer 6 REFER THE BOOK CHAPTER OF NOTES PROVIDED

Question 7

Give reason for the following:

(a) Silver nitrate Answer is kept in coloured bottles.

(b) Molybdenum is used in the manufacture of ammonia.

solution.

(d) Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.

Answer 7

(a)Silver nitrate Answer is kept in brown bottles in the laboratory because it decomposes in the presence of light.

(b)Molybdenum increases the efficiency of the catalyst iron used in the manufacture of ammonia.

(c)This is because the blue colour of the copper sulphate Answer fades and eventually turns into light green due to the formation of ferrous sulphate.

(d)Copper displaces hydrogen from sulphuric acid and forms blue-coloured copper sulphate and hydrogen gas is evolved.

Exercise-2(B), Chapter-2

Question 1

Complete the following statements:

(a)The chemical change involving iron and hydrochloric acid illustrates a _________________ reaction.

(b)In the type of reaction called_______________, two compounds exchange their positive and negative radicals.

(c)A catalyst either ______ or _____________ the rate of a chemical change but itself remains ______________ at the end Of the reaction.

(d)On heating, hydrated copper sulphate changes its colour from ________ to __________.

Answer 1

(a)Displacement

(b)Double decomposition

(c)Accelerates, decelerates, unaffected

(d)Blue, white

Question 2

When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical change involved in the two cases.

Answer 2

When hydrogen burns in oxygen, water is formed – Combination Reaction.

When electricity is passed through water, hydrogen and oxygen are given out – Decomposition Reaction.

Question 3

Explain, giving one example for each of the following chemical changes:

(a) Double decomposition

(b) Thermal decomposition

(d) Displacement

Answer 3

(a) Double decomposition reaction

This is a type of chemical change in which two compounds in solution to form two new compounds by mutual exchange of radicals

(b) Thermal decomposition

A decomposition reaction brought about by heat is known as thermal decomposition.

2HgO(s) 2Hg(s) +O2(g)

(c) Reversible reaction

A chemical reaction in which the direction of a chemical change can be reversed by changing the conditions under which the reaction is taking place is called a reversible reaction.

CuSO4.5H2O(s) CuSO4(s) + 5H2O (g)

(d) Displacement Reaction

It is a chemical change in which a more active element displaces a less active element from its salt solution.

CuSO₄ + Zn → ZnSO₄ + Cu

Question 4

(a) What is synthesis?

(b) What kind of chemical reaction is synthesis? Support your answer by an example.

Answer 4

A reaction in which two or more substances combine together to form a single substance is called a synthesis or combination reaction.

A + B → AB

In the above reaction, substances A and B combine to give a molecule of a new substance, AB. Carbon burns in oxygen to form a gaseous compound, carbon dioxide.

C + O2 == CO2

Question 5

Decomposition brought about by heat is known as thermal decomposition. What is the difference between thermal dissociation and thermal decomposition?

Answer 5

A decomposition reaction brought about by heat is known as thermal decomposition.

2HgO(s) —- 2Hg_(s) + O_{2
(g)}

A simultaneous reversible decomposition reaction brought about only by heat is thermal dissociation.

NH₄Cl NH₃ +HCl

Question 6

(a)Define neutralization reaction with an example.

(b)Give balanced equation for this reaction.

(c)Give three applications of neutralization reactions.

Answer 6

(a)The reaction between an acid and a base to form salt and water only is referred to as a neutralisation reaction.

(b)NaOH + HCl → NaCl + H₂O

(c) Applications of neutralisation reactions:

(i) When someone is stung by a bee, formic acid enters the skin and causes pain, which can be relieved by rubbing the spot with slaked lime or baking soda, both of which are bases. (ii) Acid which is accidentally spilled on to our clothes can be neutralised with ammonia solution.

(iii) If soil is somewhat acidic and thus unfavourable for growing of certain crops, slaked lime is added to neutralise the excess acid.

Question 7

What do you understand by precipitation reaction? Explain with an example.

Answer 7

A chemical reaction in which two compound in their aqueous state react to form an insoluble salt (a precipitate) as one of the product is known as precipitation reaction.

For example: BaCl₂ (aq) +NaSO₄ (aq) →BaSO₄(s) white ppt + 2NaCl (aq).

Question 8

(a)What are double displacement reactions?

(b) Give an example of double displacement reaction, where a gas is evolved.

Answer 8

(a)This is a type of chemical change in which two compound in a solution react to form two compound by mutual exchange of radicals Double decomposition reaction is also called double displacement reaction.

AB +CD→ AD +CB

(b) Double displacement reaction, gas evolved are

FeS(s) + H₂SO₄ (aq) → FeSO₄ (aq) + H₂S

Question 9

(a)What is a decomposition reaction?

(b) Decomposition reaction can occur by (i) heat

(ii) Electricity and (iii) sunlight

Give two balanced reaction for reaction

Answer 9

(a)The chemical reaction in which a compound splits into two or more simpler substance (elements or compound) is called decomposition reaction. 1 2HgO(s) —- 2Hg_(s) + O_{2
(g)}

2)DECOMPOSITION OF WATER BY PASSING CURRENT 3) DECOMPOSITION OF

SILVER NITRATE

Question 10

State the type of reactions each of the following

Answer 10

(a) Cl₂ + 2KBr → 2KCl + Br₂ Displacement reaction

(b) NaOH + HCl → NaCl + H₂O Neutralisation reaction

(d) Fe + CuSO₄ → FeSO₄ + Cu Displacement reaction

(e) PbO₂ + SO₂ → PbSO₄ Combination reaction

(f) 2KClO3 → 2KCl + 3O₂ Decomposition reaction

(g) 2H2O2 → 2H₂O + O₂ Decomposition reaction

(h) KNO₃ + H₂SO₄→ HNO₃ + KHSO₄Double decomposition reaction

(i) CuO+H₂ → Cu+ H₂O Displacement reaction

(j) CaCO₃ → CaO+ CO₂ Decomposition reaction

(k) NH₄Cl → NH₃ + HCl Decomposition reaction

(l) PbO + 2HNO₃ → Pb(NO₃) + 2H₂O Neutralisation reaction

(m) AgNO₃ + NaCl → AgCl + NaNO₃ Double decomposition reaction

Question 12 Multiple choice

(a) Which of the following is not a characteristic of a chemical change?

(i) It is irreversible.

(ii) No net energy change is involved.

(iii). New substance is formed.

(iv)Involves absorption or liberation of energy.

(b) A reaction of a type: AB + CD → AD + CD, involves

(i) No chemical change

(ii) Decomposition of AB and CD

(iii) . Exchange of ions of AB and CD

(iv) Combination of AB and CD

(c) The reaction BaCl_2(aq)+ H₂SO_4(aq) → BaSO_4(s) + 2HCl_(aq) is

(i) Displacement reaction

(ii) Neutralisation reaction

(iii) . Decomposition reaction

(iv) Double displacement reaction

(d) Thermal decomposition of sodium carbonate will produce

(i) Carbon dioxide

(ii) Oxygen

(iii) Sodium hydroxide

(iv) No other product

Answer 12

(a) (ii) No net energy change is involved

(b) (iii) Exchange of ions of AB and CD

(d) (i) Carbon dioxide

Exercise -2 (C),

Question 1

What is a chemical change? Give two examples of chemical change?

Answer 1

A chemical change is a permanent change in which the chemical composition of a substance is changed and a new substance is formed.

Examples:

Heating of copper carbonate

Formation of curd from milk

Question 2

Why energy is involved in a chemical change?

Answer 2

In every chemical change, change in energy is involved.

There is a difference between the chemical energies of the reactants and products. It involves the breaking up of chemical bonds between the atoms resulting in the absorption of energy in the form of heat and simultaneous formation of bonds with the release of energy. Question 3

What do you understand by ‘chemical reaction’?

Answer 3

A chemical reaction is the process of breaking the chemical bonds of the reacting substances (reactants) and making new bonds to form new substances (products).

A chemical change or chemical reaction occurs when particles collide. Collisions occur when reactants are in close contact or by supply of energy.

Question 4

Give an example of a reaction where the following are involved

(a) Evolution of heat

(b) Absorption of heat

Answer 4

(a) C + O₂ → CO₂ + Heat

(b) C + 2S → CS2

Question 5

State the main characteristics of chemical reactions. Give at least one example in each case.

Answer 5

(i) Evolution of gas Example:

Zn + H₂SO_{4 →} ZnSO₄ + H₂

[Zinc] + [dil.sulphuricAcid] [zinc sulphate] [hydrogen]

(ii) Change of colour Example:

Fe + CuSO4 (aq) → FeSO₄ + Cu

[Iron] [Blue solution] [Green Solution] [copper] (iii) Formation of precipitates: Example:

AgNO₃ (aq) + NaCl(aq) → AgCl(ppt) + NaNO₃(aq)

Question 6

Give an example of each of the following chemical changes.

(a) A reaction involving

(i) Change of state

(ii) Formation of precipitate

(b) An exothermic and an endothermic reaction involving carbon as one of the reactants.

Answer 6

(a) (i) Change of state

Ammonia gas reacts with HCl gas to give solid ammonium chloride.

NH3 (g) + HCl(g) NH4Cl(s)

(ii) Formation of precipitate

When a Aq, sol.of silver nitrate is added to a Aq, sol.of sodium chloride, a white insoluble substance, silver chloride, is formed.

AgNO3 (aq) + NaCl (aq) → AgCl (ppt) + NaNO3 (aq) (b) Exothermic reaction:

When carbon burns in oxygen to form carbon dioxide, a lot of heat is produced. C + O₂ → CO₂ + Heat Endothermic reaction:

When carbon is heated with sulphur at high temperature, liquid carbon disulphide is formed.

C + 2S CS₂

A few pieces of iron are added into a blue coloured copper sulphate solution; the blue colour of copper sulphate fades and eventually turns into light green due to the formation of ferrous sulphate.

Fe + CuSO₄ → FeSO₄ + Cu

Question 7

Define exothermic and endothermic changes. Give two examples in each case.

Answer 7

Exothermic reaction:

A chemical reaction in which heat is given out is called an exothermic reaction. Example:

When carbon burns in oxygen to form carbon dioxide, a lot of heat is produced.

C + O₂ → CO₂ + Heat

When hydrogen is burnt in oxygen, water is formed and heat is released.

2H₂ + O₂---à2H₂O + Heat

Endothermic reaction:

A reaction in which heat is absorbed is called endothermic reaction.

Example:

When carbon is heated with sulphur at high temperature, liquid carbon disulphide is formed.

C + 2S---à CS₂

When nitrogen and oxygen are heated together to a temperature of about 3000°C, nitric oxide gas is formed.

N_2
+ O2 ---à+ 2NO

Question 8

State the effects of endothermic and exothermic reactions on the surroundings.

Answer 8

Exothermic reactions are spontaneous and warm their surroundings with the release of heat energy.

Endothermic reactions absorb heat energy from their surroundings and cause their surroundings to cool down.

Question 9 Define:

(a) Photochemical reaction

(b) Electrochemical reaction Give one example in each case.

Answer 9

(a) It is a reaction which occurs with absorption of light energy.

Example: Photosynthesis

(b) It is a reaction which occurs with absorption of electrical energy.

Example: Acidulated water breaks into hydrogen and oxygen

Answer 10

(a) NaCl(aq) + AgNO3(aq) → AgCl(aq) + NaNO3(aq)

(b) Pb(NO₃)₂ + 2KI →2KNO₃ + PbI₂

(d) 2Pb (NO₃)₂ 2PbO + 4NO₂ + O₂

(e) 4NH₃ + 5O₂ 4NO +6H₂O

Question 11

What do you observe? When (a)Lead nitrate is heated.

(b)Silver chloride is exposed to sunlight.

(c)Hydrogen peroxide is exposed to sunlight.

(d)H₂S gas is passed through copper sulphate solution. (e)Barium chloride is added to sodium sulphate solution (f)Water is added to the quick lime.

(g)Sodium chloride Answer is added to silver nitrate solution.

Answer 11

(a)Lead nitrate decomposes on heating, leaving a yellow residue of lead monoxide, and brown nitrogen dioxide and colourless oxygen gases are evolved.

(b)Due to thermal decomposition, silver chloride breaks down into silver and chloride.

(c)Hydrogen peroxide breaks down to form water and oxygen gas along with heat energy.

(d)When hydrogen sulphide is passed through a blue Answerof copper sulphate, a black precipitate of copper sulphide is obtained, and sulphuric acid so formed remains in the solution.

(e)A white insoluble precipitate of barium sulphate is formed.

(f)Quick lime reacts vigorously with water to produce slaked lime, i.e. calcium hydroxide. (g)When sodium chloride is added to the silver nitrate solution, a white curdy precipitate of silver chloride is formed.

Question 12

(a) a carbonate which do not decompose on heating.

(b) a nitrate which produces oxygen as the only gas. (c) a compound which produces carbon dioxide on heating (d) a nitrate which produces brown gas on heating.

Answer 12

(a) Sodium carbonate

(b) Sodium nitrate

(d) Lead nitrate

Class 9 subject Biology chapter3 "Tissues"

Ans1.Meristematic tissue and Permanent tissue.

Ans2.(i) permanent tissue.

(ii) parenchyma.

(iii) Collenchyma.

(iv) Xylem and phloem.

Ans3.(i)True.

(ii)True.

(iii)True.

(iv) false, The Sclerenchyma consists of dead cells.

Progress Check(pg-30)

Ans1(i) Epithelial tissue

(ii) Glandular epithelium

(iii)Muscular tissue

(iv) Nervous tissue

Ans2(i)Ciliated columnar epithelium is located in the lining of the windpipe(trachea).

(ii)Elastic cartilage is located at the tip of the nose and external ear.

(iii) Unstrained muscles are located in the walls of the intestine and muscles of the iris of the eye.

Ans3(i)cartilage: It is elastic, on-porous and has no blood vessels and nerves.

(ii)bone: It is hard, porous and has rich supply of blood vessels and nerves

(iii) striated muscles: They are under the control of our will. They are made of long fibres which are nucleated and striated.

(iv)cardiac muscles: They are involuntary in function and found only in the walls of the heart.

Ans4(i)true

(ii)false, axons bundled together form a nerve

(iii)false, cardiac muscles do not

get tired soon.

(iv)false, epithelial cells leave no space in between

(v)false, perikaryon is the cell body of a nerve cell

(vi)false, muscles of the iris of the eye are involuntary type.

(vii)true

Review questions

Ex. A

1(c)parenchyma

2(a)fibrous connective tissue

3(a)meristem-actively dividing cells

4(d) chlorenchyma

5(d)layers of xylem in a stem

6(d) sclerenchyma

7(c)tendon

8(d) involuntary and striated

Ex. B Very short answer type:

And1(a)Apical meristem

(b)protective tissue

(d)connective tissue (ligament)

(e) conducting tissue

(f) sclerenchyma

Ans2.Parenchyma is the least specialized tissue located in plants.

Ans3.(a) tissue

(b)parenchyma

(c)lateral meristem or cambium

Ans4(a)At the tips of roots, stem and branches

(b)At the tip of nose and ear

(c)in the mouth and nasal cavity

(d)in stems and veins of leaves

(e)in the lining of windpipe (trachea)

(f)at the end of two bones

And5(a) epithelial tissue

( b)cuboidal epithelium

(c)nerve cell(neuron)

(d)ciliated epithelium

Ex. C Short answer type

Ans1Ciliated epithelium is found in the inner lining of windpipe(trachea).

The cilia present in it keep lashing and move the materials out which enter these regions.

Ans2 Nervous tissue: It is made up of elongated cells called neurons. This tissue is concerned with the perception and responses of animals.

Nervous system: It consists of brain, spinal cord and the nervous tissue. This system controls and coordinates all the systems and parts of your body.

Ans3Tissues found in human heart are:

Epithelial tissue, connective tissue, muscular tissue and nervous tissue

Ans4.No, we cannot consider because tissue is a group of cells performing a particular function but cluster of eggs cannot perform a specific function rather they perform it individually

Ans5.The three types of muscles found in the human body are:

(1)Striated muscles: found in arms and legs.

(2)Unstrained muscles: found in intestine and stomach.

(3)Cardiac muscles: found in heart.

Ex D Long answer type

An1(a)Cell and tissue:

Cell: It is the structural and functional unit of life.

E.g. nerve cell

Tissue: It is the group of similar cells performing a specific function.

E.g. connective tissue

(b)organ and organism:

Organ: several tissue make up an organ. They perform function within your body.

E.g. heart, liver

Organism: several organ system make up an organism.

E.g. humans, animals

(c)Organ and organelle

Organ: several tissue make up an organ. They perform function within your body.

E.g. heart, liver

Organelle: little organs found within the cell. They perform function within the cell

E.g. ribosomes, mitochondria.

(d)Organ and Organ system.:

Organ: several tissue make up an organ. They perform function within your body.

E.g. heart, liver

Organ system: several organs together performing a specific life process form an organ system

E.g. circulatory system

And(a)Parenchyma and collenchyma:

Parenchyma: They are the thin walled cells which may be oval, or round in shape. These cells help in the storage of food.

Collenchyma: They are the elongated cells with thickened cell wall at the corners. These cells give mechanical support to the parts of the plant

(b)Meristematic tissue and permanent tissue:

Meristematic tissue: These are made up of actively dividing cells. Cells are small usually cuboidal.

Permanent tissue: These are made up of cells which have lost their ability to divide.

Sclerenchyma: They are made up dead cells. Here, cell wall is thick. They give strength to the parts of the plants.

Parenchymal: They are made up of living cells. Here, cell wall is thin. These cells help in the storage of food.

(d)cells of involuntary muscles are spindle shaped with tapering ends. Dark and light bands are not present.

These muscles don't work according to our will while cells of voluntary muscles are long. Striations that is dark and light bands are present in these cells. These muscles work according to our will.

(e)fibres of voluntary muscles are long cells constituting voluntary muscles. They are not branched. They are found in arms, legs, face, neck, etc.

Cardiac muscles are made up of short cells but they are branched They are found in the heart.

Ans. E Structured/application questions

1 (a)The given diagram is the phloem tissue of plant as it contains the cellular components of phloem.

(b)1.sieve cell or sieve tube

2.phloem parenchyma cells

3.companion cells

4.sieve plate

(c)This tissue is likely to be found in the stem and leaves of plants.

(d)sieve tubes helps in the transport of food from leaves to storage organs and other parts of the plant.

Phloem parenchymal helps in the storage of starch and fats.

Companion cells help in the functioning of the sieve tubes.

Sieve plate allows the transportation of food as it contains perforations.

Ans2(a)This cell is nerve cell or neuron.

(b)1-Cellbody

2-Axon

3-Nucleus

4-Nissl granule

5-Neurolemma

6-Axon endings

Class 9 physics chapter2 Motion in one dimension.

Exercise 2 (a)

Q1. Differentiate between scalar and vector quantities, giving two examples of each.

Ans Scalar quantities: These are physical quantities which are expressed only by their magnitudes.

Examples:length and mass.

Vector quantities:These physical quantities requires the magnitude as well as direction to express them.

Examples:Force and weight.

Q2. when is a body said to be at rest?

Ans A body is said to be at rest if it does not change its position with respect to it's surroundings.

Q3 When is a body said to be in motion?

Ans A body is said to be in motion if it change it's position with respect to it's surroundings.

Q4 What do you mean by motion in one direction?

Ans When a body moves along a straight line path, it's motion is said to be one dimensional motion.

Q5 Define displacement. State it's unit.

Ans The shortest distance from the initial to the final position of the body. It's S. I. Unit is metre(m).

Q6 Differentiate between distance and displacement.

Ans from book, page no. 29.

Q7 Can displacement be zero even if distance is not zero? Give one example to explain your answer.

Ans yes ,displacement can be zero even if distance is not zero. For example: if a body moves in a circle, then displacement in one rotation is zero but distance covered in one rotation is circumfrence of the circular path.

Q8 Define velocity. State it's s. I. Unit.

AnsThe velocity of a body is the distance travelled per second by the body in a specified direction. Its S. I unit is ms-1.

Q9 Define speed. What is its S. I. Unit?

Ans The speed of a body is the rate of change of distance with time. Its S. I. Unit is ms-1.

Q10 Distinguish between speed and velocity.

Ans from book, page no. 32.

Q11 When is the instantaneous speed same as the average speed?

Ans When the body moves with uniform speed.

Q12 Distinguish between uniform velocity and variable velocity.

Ans uniform velocity:1when a body covers equal distance in a straight line, in equal interval of time.

2. in this case, direction of motion remains same.

3. eg.a body moving with a constant speed in a straight line has uniform velocity.

Variable velocity:1.when a body covers unequal distance in equal intervals of time in a straight line.

2. in this case, direction of motion changes.

3. eg.circular motion is example of variable velocity.

Q13 Distinguish between average speed and average velocity.

Ans Average speed:

1. it is the ratio of total distance travelled by the body to total time taken to travel that distance. Thus,

Average speed=total distance travelled/total time taken.

2. It is a scalar quantity.

Average velocity:

1. if the velocity of a body moving in a particular direction changes with time, the ratio of displacement to time taken in the entire journey is called its average velocity. Thus,

Average velocity=Displacement/total time taken

2. it is a vector quantity.

Q14 Give an example of motion of a body moving with a constant speed, but with variable velocity. Draw a diagram to represent such a motion.

Ans The motion of a body in a circular path even with constant speed, but with variable velocity because in a circular path, the direction of motion of body continuously changes with time. Its velocity changes at a uniform rate. At any instant, it's velocity is along the tangent to the circular path at that point. Fig. 2.5 from book

Q15Give an example of motion in which average speed is not zero, but average velocity is zero.

Ans if a body starts its motion from a point and comes back to the same point after a certain time, the displacement is zero, so the average velocity is also zero, but total distance travelled is not zero so the average speed is not zero.

Q16Define acceleration. State it's S. I. Unit.

Ans Acceleration is the rate of change of velocity with time. Its S. I. Unit is ms-2.

Q17Distinguish between acceleration and retardation.

Acceleration (1). Rate of change of velocity with time is called acceleration.

(2). A body falling towards the earth has positive acceleration.

Retardation (1). When velocity of body decreases with time, the motion is said to be decelerated or retarded.

(2). A ball thrown vertically upward has retardation.

Q18Differentiate between uniform acceleration and variable acceleration.

Ans Uniform acceleration:(1) The acceleration is said to be uniform when equal change in velocity take place in equal interval of time.

(2) The motion of body under gravity is an example of uniform acceleration.

Variable acceleration:(1) if change in velocity is not same in the same interval of time, the acceleration is said to variable.

(2) The motion of vehicle on a crowded road is with variable acceleration.

Q19What is meant by the term retardation? Name its S. I unit.

Ans Negative acceleration is called retardation. Its S. I. Unit is ms-2.

Q20 Give example of each type of the following motion:(a) uniform velocity:The rain drops reach on earth's surface falling with uniform velocity.

(b) variable velocity:the motion of a body in a circular path.

(d) uniform retardation:if brakes are applied on a train approaching a station to stop it.

Q21 Define the term acceleration due to gravity. State its average value.

Ans When a body falls freely under gravity, the acceleration produced in the body due to earth's gravitational attraction is called acceleration due to gravity(g). The average value of g is 9.8ms-2.

Exercise 2 (b)

Q1 What informations about the motion of a body are obtained from the displacement time graph?

Ans (1)The slope of displacement-time graph gives the velocity.

(2) The displacement-time graph is a straight line inclined to the time axis. It shows linear relationship between the displacement and time.

(3) The displacement time graph is a straight line parallel to time axis mean the body is at rest.

Q2. (a) What does the slope of a displacement time graph represent?

Ans The slope of a displacement time graph gives velocity.

(b) Can displacement time sketch be parallel to the displacement axis? Give reason to your answer.

Ans No, the displacement time graph can never be a straight line parallel to the displacement axis because such a line would mean that the distance covered by the body in a certain direction increases without any increase in time(I.e.velocity of the body is infinite) which is impossible.

Q3 Draw a displacement time graph for a boy going to school with a uniform velocity.

Ans from the book at page no 37 figure 2.8

Q4 State how the velocity time graph used to find (1) the acceleration of a body

Ans: acceleration=velocity÷time, if slope is positive mean accelerated motion. If slope is negative mean retardation. If slope is zero means acceleration is zero.

(2) the distance travelled by the body in a given time(3) the displacement of a body in a given time.

Ans The distance travelled by the body in a given time can be obtained by finding area enclosed between the velocity time graph and X axis gives displacement of the body. Total distance travelled by body is their arithmetic sum(without sign)

The total displacement is obtained by adding them numerically with proper sign.

Q5 Draw a velocity time graph for a body moving with initial velocity u and uniform acceleration a. Use this graph to find distance travelled by the body in time t.

Ans from book at page no. 51,figure 2.45.

Distance travelled by body in time t=area of Trapezium OABD

=area of rectangle OAED+area of triangle ABE

Or S=OA*OD+1/2*BE*AE=ut+1/2(v-u) *t

=ut+1/2at2.

Q6 Draw the shape of the velocity time graph for a body moving(a) uniform velocity, (b) uniform acceleration.

Ans from book at page no. 40,fig 2.13 for part a and fig 2.14 for part b.

Q7 Draw a graph for acceleration against time for a uniformly accelerated motion. How can it be used to find the change in speed in certain interval of time?

Ans fig. 2.19 at page no. 42

Since acceleration=velocity÷time

therefore, acceleration×time=change in speed. So in the given graph the area enclosed between the acceleration time sketch and time axis gives change in speed of the body.

Q8 Draw a velocity time graph for the free fall of a body under gravity, starting from rest. Take g=10ms-2.

Ans figure 2.22 at page no. 43

Q9 A body falls freely from a certain height. Show graphically the relationship between the distance fallen and square of time. How will you determine g from this graph?

Ans fig. 2.24 at page no. 44

The value of g can be obtained by doubling the slope of the S-t2 graph for a freely fallig body.

Please learn and write on your copies.

History Class 9 - Chapter 2 structured questions

( based on 2019 edition)

1. With reference to the sources of information about the Vedic age......

a. The Vedas. b. The Epic c. Role of iron implements

Ans- a. The social, economic, political and religious aspects of the life of the people came to be reflected in the Vedic literature. Thus, Vedas became the storehouse of knowledge. The Vedic literature was written in Sanskrit. The term, Veda' has been derived from the Sanskrit word, 'vid' which means knowledge.

b. The Epics serve as the main source of information on the political institutions and the social and cultural organisation of the Epic Age

(ii) They provide information on various Aryan Kingdoms, their armies and the weapons they used.

iii.They reveal the high ideals of family life of the Aryans.

c. i. Agriculture: Discovery of iron gave the Aryans new implements like axes to clear the forest and cultivate the land.

(ii) Occupation: The use of iron gave rise to new trades by providing durable implements like saws, chisels, hammers, nails and tongs.

(iii) Defence: Because of its durability and easy availability, iron was extensively used in making weapons like swords, armours and shields.

2. With reference to Vedic Literature, answer the following questions:

(a) List the categories into which Vedic literature is divided.

(b) Give a brief account of the four Vedas.

Ans- a. The Vedic literature can be classified into the following categories: (i) The four Vedas, i.e., the Rig, Sama, Yajur and Atharva Vedas and their Samhitas. (ii) The Brahmanas attached to each Samhita (iii) The Aranyakas (iv) The Upanishads.

b. i. The Rig Veda : It is the oldest religious text of the world. It is said to have been composed during the early Vedic Period . The hymns are dedicated by the sages to Gods

ii.

) The Sama Veda: In this veda some of the hymns are borrowed from the Rig Veda, These hymns were meant to be sung at the time of the sacrifice by the priests]

(iii) The Yajur Veda: (It deals with hymns recited during the performance of Yajnas

(iv) The Atharva Veda: The hymns contained in this Veda deal with magic and charm. Most of the hymns are taken from the Rig Veda.

c. The Brahmanas

Written after the Vedas as their simple commentary, the Brahmanas are in prose. They explain the social and religious importance of rituals as well as the value of sacrifices.

The Aranyakas

They are known as forest books' written for the guidance of the hermits and the students living in forests.

3. With reference to the Society during the Vedic Age, answer the following

(a) Explain briefly the class divisions that existed in the society. (b) Explain the four stages in the life of an Aryan.

a. People followed different professions which became hereditary in course of time. This resulted in the division of society into occupational stages classes. Gradually, this took the form of caste and the present caste system emerged. In the Later Vedic Period, Brahmins, Kshatriyas, Vaishyas and Shudras became four distinct castes or Varnas.

b. i. The The Brahmacharya Ashrama lasted upto the age of 25 years. During this period, the pupil was expected to acquire knowledge in the gurukul and observe strict discipline.

ii.Grihastha Ashrama,25 to 50 years

Man was supposed to marry and raise a family. As a householder, he was to take responsibility of maintaining his family.

iii. The third stage was Vanaprastha Ashrama,50 to 75 years.

During this period man was expected to retire from worldly life and acquire spiritual and philosophical knowledge.

iv. The Sanyasa Ashrama,75 to 100 years.

This was the period of renunciation. Man had to leave everything forever and go into meditation in order to attain moksha or salvation.

c. POSITION OF WOMEN

During the Rig Vedic Period women were respected. The institution of marriage had become sacred. The daughters were given freedom to choose their husbands.

In the Later Vedic Period, there was significant decline in the status of women.They did not enjoy the right to property. The freedom to choose husbands by women was curtailed.

4. With reference to economic organisation of the people in the Vedic Period, answer te following questions:

(a) State the methods used by the Aryans in agriculture.

(b) Why was domestication of animals important to the Aryans? (c) How was trade managed during this period?

Ans- a. Agriculture: Discovery of iron gave the Aryans new implements like axes to clear the forest and cultivate the land. Thus, agriculture became their important occupation. With the use of iron plough-heads, sickles and hoes, they could bring vast tracts of land under cultivation. The production of more rice, wheat, barley, vegetables and fruits improved their standard of living.

b. In the beginning the main occupation was domestication agriculture was secondary. Cattle was the important source of wealth.Cows were domesticated and milk and milk products like curd, butter, ghee, etc. were used.

c.Trade:During the Later Vedic phase agricultural surplus led to trade, giving rise to markets from which developed towns and cities. Thus, trade became the pivot around which the whole town and city life moved. Although the Aryans had introduced coins, barter system was still dominant in trade with other countries.

5. With reference to the picture given, answer the following questions:

(a) Identify this ancient education system. Persons belonging to which ashrama of life attended this?

(b) Describe briefly the life in this ancient education institution.

Ans- a. This system was known as Gurukul system of education.

The person belonged to the Brahamacharya Ashrama.

b. The student was required to do household chores for his teacher. He had to get up early in the morning, take a bath and chant the Vedic mantras. Most of the teaching was done orally. At the completion of the education, a student used to give guru dakshina – a gift to his teacher.The main object of education was to bring about physical, mental and spiritual development of the pupils.

c. Advantages;

i. It was focused on all round development of a student like mental, physical etc.

ii. Pupils learnt to live a disciplined life.

Disadvantages;

i. Pupils had to left the home at tender age which deprived them from parental love.

ii. There was no formal system of evaluation.

History Chapter 1 structured questions

Answer

a. The great bath: it indicates the following

1. the art of building had reached a high degree of perfection.

2. There might have existed a ruling class that could mobilize labour.

3. The importance attached to ceremonial bathing

4. The efficient planning in the structural features relating to water supply

b. The seals:

1. These are used by the Harappans to show their artistic skills.

2. These provide useful information about script, trade, religion and beliefs.

3. These were used by the traders to stamp their goods.

C. script : the harappans used a script which is regarded as pictographic since its signs represent birds, fish and varieties of the human form. The number of signs of harappan is known to be between 375 and 400.

Q2. answer:

a. In 1921, dayaram sahni an officer in the archaeological department. Survey of India got ruins dug out, around harappa. In 1922, R.D Banerjee along with a biddhist monk found the city of mohenjo daro under a mound. Later, sir john marshall ordered large scale excavations.

b. The entire area of the harappan civilization is triangular in shape covering an area of about 1,299,600 sq. km, extending from sutkagendor in balochistan in the west to alamgirpur, in ganga yamuna doab and from manda in jammu in north to bhagatrav in narmada estuary in the north.

c. Manda, banawali, kalibangan, alamgirpur, lothal rupar and rangpur.

Q3. answer:

a. Town planning: it is the most remarkable feature of the Harappan civilisation. The indus cities were set up on a grid-pattern, consisting of regular planning with division, alignment of streets, planning of the houses and public building with the provision of thoroughfares.

b. Special features of the houses: the houses at street corners were rounded to allow carts to pass easily and the house drains emptied all waste water into the street drains.

c. Common elements: given on page no. 9 shaded portions.

Q4. answer:

a. A large number of stone images have been found; out of these the statue of a yogi draped with a shawl is well-known. Bronze statues of a dancing girl, animals and carts etc. are noteworthy.

b. Harappans produced their own characteristics pottery which was made glossy and shining. Earthen vessels and pottery crafted on the potter’s wheel, were decorated with black geometrical designs. The large jars with narrow necks and red pots with black decoration bear evidence of their artistic skill.

c. The sculpture in metal was done through the special lost wax process. In this process wax figures were covered with a coating of clay. Then the wax was melted by heating and the hollow mould thus created was filled with molten metal which took the original shape of the object.

Q5 answer:

a. The seal given in the picture is a pashupati seal.

The seals were used for trade in the vast area of indus valley, as these have been found from various spots spread over the civilisation sites. The seals with short inscriptions gave some message which cannot be deciphered yet.

b. The seals were made of terra-cotta, steatite, agate etc.

c. The seals reveal the mythical and religious beliefs. The figures carved in the seals depict the worship of mother goddess and Pashupati and various animals, trees etc.

Q6 answer:

a. The picture is of a great bath.

1. It has a large rectangular tank in a courtyard surrounded by a corridor on all four sides.

2. There are two flights of steps one in the north and the other in the south leading into the tank.

b. . same as first a.

C. the citadel: the raised area of each city was called the citadel. It owed its height to the buildings constructed on mud brick platforms. The citadel had the houses of the ruling class and important buildings like the great bath, the granary, the assembly hall and the workshops.

Chapter 3 jainism and buddhism

Q1 answer

a. Same as 1 short answer.

b. Same as 2 short answer.

c. Jatakas : the jatakas tales written in pali language refer to the previous birth of lord buddha. They also throw light on the political, economic and social conditions ranging from the fifth to second century.

Q2. answer:

a. Monopoly of the priests, expensive rituals, difficult sanskrit language and rigid caste system universally affected the life and feelings of the common people. Some kings had also realised certain social evils and so patronised Jainism and Buddhism for a better pattern of life and simple rules for spiritual uplift. Ahimsa and the safety of animals were also prefered by farmers.

b. Causes for the rise of jainism and buddhism :

1. Corruption in the religion: in order to extract money, priests encouraged ordinary people to perform yajnas and conduct household rites beyond their means.

2. Rigid caste system: the division of society becomes rigid. It did not allow any mobility. A person of one caste could not become a member of another society.there were restrictions on the basis of caste.

3. Difficult language: vedic literature was written in sanskrit which was very difficult to understand and it gave birth to the monopoly of brahmins over religion. They started exploiting other castes.

4. Political impact: the republics of shakays, vajjis, and mallas embraced buddhism ashoka and kanishka made buddhism their state religion.

c . when bhadrabahu took jainism to karnataka; at the same time sthulibhadra in magadh spread jainism with different ideas. So after the first jain council held around 300BC, jainism was divided into two groups or sects.

Q3. answer:

a. Mahavira was the twenty fourth and the last of the tirthankaras. He made Jainism popular and systematic. Mahavira was born in kundagram near vaishali in bihar in the 2nd half of the 6th century B.C.

b. He got absorbed in spiritual pursuits from early childhood. At the age of thirty, after the death of his parents,Mahavira renounced the world and became ascetic. He practised severe penance for 12 years and attained supreme knowledge.

c. Mahavira conquered all worldly desires and was named as jina, which means the conqueror.

Q4. answer:

a. Nine truths:

1. Punya (results of good deeds).

2. Pap (sin)

3. Ashrav (good deeds)

4. Sanvar (hindrance in the way of karma)

5. Nirjara (destruction of the karmas)

6. Moksha (salvation)

7. Jiva (living things)

8. Ajiva (non living things)

9. Bandha (bondage).

b. . doctrines:

1) triratnas : right faith, right knowledge, right conduct.

2) Karma: good deeds provide moksha.

3) Equality: universal brotherhood.

4) Eternal soul: soul is immortal.

5) Belief in penance: sacrifice of physical desires,

6) Salvation: freedom from life and death.

C. causes

1) Jainism preached rigid austerity.

2) The religion did not spread to the foriegn countries.

3) Jainism did not get royal patronage.

4) Hinduism revived during the Gupta period.

a. Gautam buddha was the son of sakya king, suddhodana of kapilvastu. He was born in 563 B.C at lumbini. After studying under renowned teachers of rajgriha, he went to gaya and practised severe penance and at the age of thirty -five he attained enlightenment.

b. After enlightenment he preached his first sermon at deer park sarnath this incident is known as dharmachakrapravartana.

c. He established a bodh sangha at magadha. He received the patronage of several rulers of magadha, kosala and kosambi and followed by a large number of followers from all classes of society.

Answer:

a. Membership: the members of monastic order required to renounce the world before joining the sangha. The members had to take the oath, they also had to undergo training for 10 years.

b. 1. To speak the truth.

2. Not to harm the creatures.

3. Not to keep money.

c. The principles of Buddhism have a deep effect on social life. Which gave impetus to weaker sections of the society to fight for their rights and survival. The social-religious reform movements were the plus points and the solid political ground.

Q7 answer:

a. 1) Gautam buddha founded Buddhism. 2) Mahavira founded the jainism.

b. Main teachings

1. Ahimsa i.e non violence.

2. Asateya i.e not stealing.

3. Satya i.e not telling a lie.

4. Apargriha i.e not possessing property.

5. Brahamcharya i.e practising chastity.

Four noble truths:

1. The world is full of suffering.

2. The suffering has a cause.

3. Desire is the cause of suffering

4. If desire is stopped, suffering can also be stopped.

C. similarities:

1. Both did not accept the vedas.

2. Non-violence was their creed.

Dissimilarities:

1. Buddhism followed a middle path but Jainism believed in hard penance.

2. It is silent about the existence of god whereas jainism denies the existence of god.

GEOGRAPHY

STD IX CHAPTER 5

LANDFORM OF THE EARTH

Ans 1 Plains are comparatively flat and a level surface of land with least

in its highest and lowest points

Ans 2The process of mountain building that occurs on large scale. Literally, the birth of mountain.

Ans 3 The different types of mountains are fold mountain, block mountain and volcanic mountain.

Fold mountain- These mountains have been formed due to the sedimentary deposits and large scale earth movements caused by tectonic force . e.g. Himalayas, Alps, Andes etc.

Block mountain – These mountain have been formed due to faulting in the ground surface. E.g. Vosges and black forest Mt.

Volcanic mountain- These mountain have been formed by the accumulation of lava around the crater which is thrown out during a volcanic eruption.e.g.fujiyama and Mauna loo.

Ans 4 An extensive almost flat topped region is called plateau.

Ans 5 The various typed of plateaus are:

[1] Intermundane plateau eg Columbia plateau in north America.

[2] Piedmont plateau eg Patagonian plateau in south America.

[3] Volcanic plateau eg Deccan plateau in India.

Ans 6 Advantages of plains are :

1- They are extensive area of lowland.

2- Many of them are smooth or have a gentle undulating surface.

Ans 7 Following are the types of depositional plains.

1 Alluvial plains These are formed by the depositional work of rivers and are divided into three categories.

a-piedmont alluvial plains-These are formed at the foothill of the mountains, due to the deposition of the material like cobbles, pebbles, boulders

B-Flood plains- A low lying area near a stream.

C – Delta plains-These are formed at the mouth of a river in the lower valley

2-Loess plains- These are formed by the depositional work of wind.

3-Glacial depositional plains-these plains are formed by the depositional work of glaciers

Ans 8 The main uses of mountains are –

1-They are the storehouse of minerals like coal, iron ore, gold etc.

2-They are the source of rivers.

3-They are important for their natural vegetation.

4 They are a natural barrier and also form an important political boundary

5 They have a great impact on the climate.

Ans 9-The difference between intermundane plateau and volcanic plateau;

INTERMONTAIN PLATEAU are surround by mountain. Their surface show an variety of topographic features for eg. Plateau of Tibet and Mexican plateau.

VOLCANIC PLATEAUS are formed by lava flow from volcanic eruption for eg. The plateau of peninsular India.

Ans 10 Plains are flat and level surface of land with least difference in its highest and lowest point .They are extensive area of low land.

AND Plateau is an extensive flat topped region.

Ans 11 A mass of very high rock rising to great height above the surrounding areas is called mountains.

Ans 12 CHARACTERISTICS OF YOUNG FOLG MOUNTAIN:

[1] These have been formed in the most recent phase OF Mountain building.

[2] They have rugged relief feature.

Ans 13 The mountains of young fold type are characterized by ruggedness of relief and rounded contours of mountain areas which have been subjected to weathering agents for long period of time.eg. the alps and the Scottish highlands.

Ans 14 Alluvial plains are formed by the depositional work of river.

Ans 15: [1] Fold mountains eg Himalayas.

[2] Block mountains eg African rift valley.

[3] Volcanic plateau eg Deccan plateau.

[4] Structural plain eg. The great plain of USA.

[B] DEFINE THE FOLLOWING :

[1] same as ans 9

[2] Block mountain- see ans 3.

[C] DIAGRAMS:

[1] FIG 5.5

[2]FIG 5.11

Class-9 Geography Ch-2 Latitudes and Longitudes Ex-A

Answers the following:-

1]We need to locate places on earth because earth is a huge planet & to know it properly
we need to locate place.

2]The latitude of a place is the angular distance of that place north or south of the
equator,as measured from the centre of the earth.

3]Pg.-30 from technical terms.

4]Because there is no land mass beyond 90° north & 90° south.

5]These lines are called meridians,meaning "mid-day" as all the places on the same
meridians have their noon at the same time.

6]pg-29,content analysis 4th point

7]phg-29-30,content analysis 6th point

8]The distance between each latitude,is approximately 111KM,as earth represent 360°
and the circumference of te earth is approximately 40000KM. THUS,40000/360°Pg-30
content b=111KM

9]The north temperate lies between 23 1/2° N to 66 1/2° N and south temperate
zone 23 1/2° S to 66 1/2°.stretch from torrid zone to frigid zone

10]Because torrid zone receives direct rays of the sun.

11]Because of inclination of earth's axis and recieve very slant rays of the sun.

12]Local time of a place is that time when sun is overhead to meridian.It is fixed by
the apparent movement of the sun.

13] YES

14] 1°=4min
30°=4x30=120min or 2hrs
12noon +2hrs=14hrs or 2pm

15]If each city werre to keep the time of its own meridian,there would be much diffrence
in local time betweeen one city and another.Therefore, a system ofr standard time is
observed by all countries

16]Pg-30 from technical terms.We have 24 time zones.

17]Because singapore lies in the torrid zone and london lies in the temperate zone.

18]pg-30 content analysis g point.international date line is a line concerned with
the dates of the calender and adopted international.

19]Due to its large east west extent.

20]Except the equator,other parallels of latitudes are known small circle.

21]Because these latitudes do not divide the earth into two equal half.

22]If each town,village anf city in the world had kept its on time it would have cause
utter confusion,as the clocks and watches would have to be constantly altered as one
travelled from one place to another.

23]Pg-30 from technical terms.

24]Earthosthens.

25]Important climatic zones of the world are- The Torrid or Tropical zone,Temperate zone
and Frigid zone.

26]The earth takes 24 hrs to run throw 360 degrees.The sun appears to moves at the rate
of 15° in 1hr or 360°in 24hrs or 1°in 4 minutes.

27]The intrection of latitude and longitude at right angle is the extact position of a
place on the earth's surface.latitude give us the location of any place in northen
and southern hemisphere while longitude help us locate the place in eastern or
western hemisphere.with the help of these intersecting line we can locate the
position of any place on the globe or map.

28]
1-Latitude
2-Longitude
3-40°North

29]
A-Local Time-Local time of a place is that time when sun is overhead to the meridian.
it is fixed by the appearent movement of the sun.

Standard Time-Most country adopt their standard from the local time of their central
meridian.for eg-India follows the local time of its central meridian 82 1/2° East
which passes throw Allahabad.

B-Parallel run from east to west and never intersect with each other whereas
meridians run from north to south and intersect at north and south poles.

C-Equator separates the Northern and Southern hemispheres.The equator is at 0°latitude.
the prime meridian separates the Eastern nad Western hemispheres.The prime meridian
run through Greenwich,England and is at 0°Longitude.

ex-B,Define the terms:-
1,2,3,4 from technical terms pg-30
5,6 same ans 29a

7-In india the longitude 82 1/2° East is selected as standard meridian,which passes
which passes through Allahabad.since its local time is taken as standard Time,the
whole country follows it,it is called indian standard time.

8-pg-30 content analysis F point
9-same ans 18

10-The 0°Latitude is known as great circle.It divides the earth into two equal halves

11-same ans 20

12-Same ans 23

Ex-c
Distinguish between the following:-
1-pg-29 table 2.1

2-from ex-b 10 and 11 define

3-from ex-b 8 & 7 define

EX-D
Give reasons:-
1-Because latituides are angular distance of a place north and south to the equator and
longitude are the angular distance of a place east and west to the prime meridian.

2-Due to large east-west extent.

3-To avoid cutting through the continent.

4-Because the places east of greenwich see the sun earlier and gain time or Because sun
rise in the east and set in the west.

5-Because latitudes are parallel to each other.

6-Because mumbai lies in the east of prime meridian and london lies in the prime
meridian.

7-The difference between the indian standard time and the greenwich is 82 1/2°,i.e.,
5 1/2 hrs.0° to 82 1/2°east =82 1/2°X 4=330 minutes or 5 1/2 hrs.

Ex-E

1-pg-21 fig.2.7
2-pg-23 fig.2.10
3-pg-20 fig.2.3

Dear students some questions are not given in new book. Here we are adding few questions to cover inside portion.

Class 9^th history and civics harappan civilisation

I. Short answer questions:

QUESTION1. what is meant by the term civilisation?

Answer:

Civilisation is defined as an advanced stage of human cultural development it ipmlies the use of superior technology and complex economic relationships. Following are the traits which mark a civilisation:

1. Surplus food

2. Division of labour

3. System of writing

4. Development of technology

Question2. mention any three features that led to the emergence of civilisation

Answer:

1. The ruins of the sites reveal that the harappan people were primarily urban and their cities were designed skillfully.

2. The unique features of the city was its elaborate drainage system. A brick-lined drainage channel flowed alongside every street.

3. The great bath was also unearthed. The pool was filled with water taken from a well nearby. The walls of the pool were made.

QUESTION3.

What are known as bronze age civilisation?

Answer:

Man learnt the art of mixing copper with tin of zinc to produce the alloy called bronze. Bronze is hard and more ductile than copper and is therefore, more suitable for the mannufacture of tool and weapons. Because of the importance of bronze in the growth of the civilisations, these civilisations are known as the bronze age civilisation.

QUESTION4

Name the important sources of information on the harappan civilisation

Answer:

The archeaological remains

Seals, sculptures

QUESTION5.

Why did ancient man start using bronze for making tools and weapons

Answer:

Ancient man start using bronze for making tools ans weapons because bronze is harder and more ductile than copper. Therefore, it is more suitable for the manufacture of tools and weapons.

QUESTION6.

Why is harappan civilisation called so?

Answer:

The harappan civilisation is called so because the harappan site was the first to be discovered in 1921 at the modern site of harappa situated in the province of west punjab in pakistan.

QUESTION7.

What types of weights and measures did the indus people use?

Answer:

The indus people used sets of cubical stone weights. The basic unit was 16(equalto mmodern 14 grams). the larger weights were multiples of 16 like 32,48,64,128 and so on. The smaller ones were all fractions of 16.

QUESTION8.

Name one important public building of indus valley civilisation and its importance.

Answer:

The great bath is one of the largest public buildings at mohen-jo-daro. It was used by a large group of people while performing some religious rituals.

QUESTION9.

Name the process by which sculpture in metal was done

Answer:

It was known as lost wax process.

QUESTION10.

QUESTIONwhat do you know about the indus script?

Answer:

Indus scripts has not been deciphered as yet. So the only source of script are some seals and copper tablet. Seals display some sort of pictorial writing. Besides this similar inscriptions have been found engraved on copper tablets with figures of men and animals.

QUESTION11.

Mention the types of dress worn by the indus valley people.

Answer:

Most people used cotton clothes. Rich people also used woollen clothes in winter. The women’s dress included skirts, cloaks and scarfs and the men’s dress was dhoti and shawl. Spinning wheels and needles of that time prove the art of spinning was practiced by the people.

QUESTION12

State two features of the trade in the indus valley civilisation.

Answer:

1. the harappan carried on considerable trade in stone, metal, shell etc.

2. They however, did not use metal money but carried on all exchange through barter system

Question13.

Name three animals depicted on pashupati seal

Answer:

Seals of pashupati shows a three faced deity wearing a buffalo-horned head dress, seated cross legged on a throne and surrounded by an elephant, a tiger, a buffalo and a rhinoceros, with two deer at his feet.

QUESTION14.

State any two causes that led to the decline of the harappan civilisation

Answer:

1. Floods and earthquake: it is held by some scholars that floods in mohenjo-daro led to the abandonment.

2. Attack: some historians believed that the invading aryans destroyed the indus valley civilisation.

QUESTION15.

In what two respects is harappan civilisation our greatest heritage?

Answer:

The harappan civilisation present a basic ground of indispensible heritage which imparts a soild imprint on the latter civilisation e.g the way of making baked pottery, bricks, beads jwellery etc the cultivation of cotton was adopted by the egyptians after several centuries.

QUESTION16.

Give two characteristic features of the citadel

Answer:

It owed its height to the building constructed on mud brick platforms. The citadel had the houses of ruling class and important building like the great bath, the grannary, the assembly hall and the workshops.

QUESTION17.

How were seals used? What information do they give about harappan trade?

Answer:

The seals were used by traders to stamp their goods. After a bag with goods was tied, a layer of wer clay was applied on the knot, and the seal was passed on it. These seals were found in different regions. This indiacates that the harappan trade had spread over a vast area.

QUESTION18

Briefly describe granaries at harappa.

Answer:

In harappa there were two rows of six granaries each. To the south of the granaries at harappa working floors consisting of rows of circula brick platforms were discovered. It is believed that these floors were meant for threshing grain because wheat and barley were found in the crevices of the floors.

QUESTION19.

Breifly describe the ornaments.

Answer:

Ornaments were worn by both men and women. Some of the common ornaments were necklaces, finger -rings, bangles, armlets, anklets, nose rings, fan shaped gead dress and earings. They were made gold, silver, precious stones and ivory.

Question20.

Breifly describe the dancing girl.

Answer.

The bronze statue of a dancing girl, found at mohen jo daro, is a masterpiece of art and it shows a high degree of development in art of sculpture. The figurine shows vigour, variety and ingenuity. The right arm of the dancing girl rests on the hip and the left arm in heavily bangled. It holds a small bowl against her left leg.

QUESTION21.

Mention the evidences which suggest that the harappan peoplehad trdae relations with other counteries.

Answer ;

1. The mesopotamian records from about 2350 BC refer to trade relations with meluha(name given to indians)

2. objects of sumerian origin found at the ruins of the indus cities indicate that their trade relations between these countries were actively practised into.

3. The seal bearing a mastless ship holds the evidence of popularity of the sea routs

NOTE: These include some internal part also.

Chapter 2. Vedic Period

QUESTION1 name the categories of vedic literature. Why was early vedic literature is known as shruti?

Answer:

Vedic literature is divided into two categories:

1. Early vedic literature( Shruti)

2. Later vedic literature (samriti)

It is believed that four vedas and its parts( the brahmanas, the Aranyakas, the upnishads) are given by god to sages by hearing(shruti means which is heard) and so it is called Shruti.

QUESTION2.

Name the four vedas and state what the hymns in each veda deal with?

Answer:

Four vedas:

1. The Rig veda.

2. The sama veda

3. The Yajur veda

4. The Atharva veda

1.The hymns of rig veda dedicated by the sages to the gods. It contains the famous gayatri mantra.

2. the hymns of sama veda sung at the time of the sacrifice by the priests

3. the hymns of Yajur veda deals with rituals perfomed at the time of Yajnas.

5. the hymns of Atharva veda deals with the power of ghosts, spirits, gyan, karma and upasna.

QUESTION3.

What are upnishads?

Answer

The Upnishads are philoshophical commentaries on the vedas. These form the basic source of indian philoshophy. They are said to form the foundation on which later additions to vedic literature rest.

QUESTION4

What are dharmashatras?

Answer

The law- books called the dharmashatrasand the samritis together with their commentaries are called dharmshastras.

Question5

What is known as bhagwad gita?
Answer:

Bhagwad gita is the compilation of the text, teachings imparted by lord krishnato arjun explaining the importance of Karma or duty, immortal soul, the right way of life. It also includes the glimpse of mahabharat battle. It is a sacred book of hindus.

QUESTION6.

Mention the importance of the Epics as a source of information about the aryans.

Answer.

1. these inform about the political, social and cultural organisation of the epic age.

2. these provide information about aryan kingdom.

3. These reveal the high ideals of family life of the aryans.

QUESTION7

Which battle is known as the mahabharata

Answer: the battle between kurus and pandavas along the battlefield of kurukshetra is known as the mahabharats.

Questiion 8

Give two features of painted grey ware.

Answer:

The PGW is a very fine, smooth and even-coloured pottery. It was made out of well worked, high quality clay with geometric patterns painted on it in black colour. Floral pattern and sun symbols are seen in some cases. The pottery include open mouthed bowls and dishes.

QUESTION9

How did trade become a pivot(central point) around which the life of the people revolved?

Answer:

During the later vedic age, trade became quite prominent; so the settlement or the towns and cities developed around the main trade centres. Thus, the city life moved according to the activities associated with the trade.

QUESTION10

What was the role of iron?

Answer

Iron played a significant role in the lives of peasants as the use iron became popular for making agricultural tools. Iron ploughshares and metal tools were used and a variety of crops cultivated.

QUESTION11.

State the difference in the position of women between the early vedic age and later vedic age.

Answer:

During the early vedic period wome were respected. The institution of marriage had become sacred.

The daughters were given freedom to choose their husbands.

In the later vedic age, there was significant decline in the status of women. Their participation in yajnas was not considered necessary. They did not enjoy the right to property. Man’s opinion were respected. As a result the freedom to choose the husbands by women was curtailed.

QUESTION12

What are varnas? Name them

Answer;

Varna was a division on the basis of skin colour. In vedic age it became popular as the society was divided into four varnas. Brahmins, Kshatriya, vaishayas and shudras.

QUESTION13.

Name the four ashrams into which the human life span was divided, indicating the time span for each

Answer:

The four ashramas are Brahmacharaya, Grihastha, Vanaprasthas and sanyasa

1. Brahmacharya ashrama: it lasted upto the age of 25 years. During this period, the pupil was expected to acquire knowledge in the gurukul and observe strict discipline.

2. Grihastha ashrama: during this peiod, man was supposed to marry and raise a family. This perios lasted from the age of 25-50 years.

3. Vanaparastha ashrama: it lasted from the age of 50-75 years. This period man was expected to retire from worldly life and acquire and philosophical knowledge.

4. Sanyasa ashrams: the last stage lasts from the age of 75 to 100 years this period of renunciation

QUESTION14.

State the change that occured in the position of brahmins in the later vedic age?

Answer:

In the later vedic age brahmins or the priests performed religious rituals. The caste system become rigid. The priests came to be considered as gods on earth.

QUESTION15.

State three important changes that took place in the society in the process of its transition from early vedic period to the later vedic period.

Answer:

Three changes:

1. Single family converted to joint family.

2. Equal rights enjoyed by women changed to declination in status of women.

3. General caste system converted to rigid caste system.

Question16

Difference between the economy of early vedic age and later vedic age.

Answer

Early vedic age:

In the beginning the main occupation was domestication of animals and agriculture was secondary.

Cattle was the important source of wealth.

Many engaged in trade and commerce. Dyeing, embroidery;carpentry, weaving, pottery, crafts in gold and iron were important occupations.

Later vedic age:

Agriculture became the chief accupation while domestication of animals also continued.

Land was the important source of wealth.

Traders guilds had come up and trade had become very important. Besides occupation of earlier period, many new occupations like physicians, musicians, and many other profession emerged

Note : these questions will include an inside portion.

Class 9th subject history and civics

Chapter 1 of civics

Question 1:

What is meant by the term constitution

Answer:

The Constitution is a comprehensive document containing the set of rules according to which the government of a country runs. It regulates the position and powers of three organs of the government- the legislative, the executive and judiciary.

Question 2:

On the basis of which plan was the constituent assembly constituted?

Answer:

Cabinet mission plan.

Question 3

What is objective resolution?

Answer:

Objective resolution was proposed by pt. Jawahar lal nehru on december 13, 1946 for highlighting the national goals.

Question 4;

By whom was the objective resolution proposed?

Answer:

It was proposed by the Pt. Jawahar Lal Nehru.

Question 5:

Who was appointed as the chairman of the drafting committee of the constitution?

Answer

Dr. Bhim Rao Ambedkar was appointed as the chairman of the Drafting committee.

Question 6:

When was the constitution adopted and passed? When did it come into force?

Answer

Adopted and passed: 26 November 1949.
Come into force: 26 January 1950.

Question 7:

State the significance of January 26.

Answer :

It was on this date, January 26, in 1929, that the lahore session of the indian national congress had for the first time given the call for purna swaraj. Since then, the day was celebrated as independence day upto 1947, but later on, it was designated as the republic day.

Question 8:

What is the preamble?

Answer :

The Preamble is the introductory part of the constitution, which sets out the main objectives of the constitution.

Question 9;

Explain the significance of the term sovereign.

Answer:

It means that India is its own supreme power and not a subject of any other state or country.

Question 10.

Mention any two features indicating the significance of the preamble.

Answer:

1.The preamble represents the essence, the philosophy, the ideals of the entire constitution of india.

2. It contains the five basic features of the constitution ie. sovereign, socialist, secular, democratic and republic.

Question 11.

Who represented the anglo indians in the constituent assembly /

Answer

Mr. frank anthony and S.H prater

Question 12.

Why is our constitution known as the fundamental law of the land?

Answer

Being superior to the ordinary law of the state, the constitution of India is known as the fundamental law of land.

Structured questions

Question 1

With the reference to the making of indian constitution explain the following

Part a.

When and how……...elected?

Answer 1.

The first sitting of the assembly was held on december 9, 1946

The cabinet mission plan arrived in India in 1946 and put forward a set of proposals to meet the demands of freedom fighters. One of these proposals involved setting up of a constituent assembly whose members were to be elected indirectly by the provincial legislative

assemblies.

Part b.
How was the membership……..partition of the country?
Answer

The muslim league boycotted the constituent assembly consequently the members representing the territories went to pakistan withdrew from the cosntituent assembly of india. As a result, the membership of the constituent assembly of india stood at 299n against the original number of 385.

Part. c how can you say that constituent …………….of the indian society.

Answer:

The wide ranging membership of the constituent assembly gave representation to all shades of public opinion.it was composed of members from all the categories and communities belonging to india.

Question 2

With the reference to objective resolution

Part a.

Same as the 4th answer. Indian idependence act 1947 gave legal sanctity to the constituent assembly.

Part b

Main points

Answer1.

India will be a republic.
The ideals of social, political and economic democracy would be guaranteed to all the people.
The republic would grant fundamental rights to citizens.
The state would safeguard the rights of backward and minorities.

Part c.

Three principles

Answer:

Making indian constitution workable, flexible and strong enough to hold the country together both in peace and in war.
Providing special safeguard to the minorities.
Incorporating the right to constitutional remedies.

Note: these questions cover the inside portion also.

9th Class Chapter 3rd Jainism and Buddhism

Question 1 angas and subject matter

Answer

Jain scriptures are popularly known as agamas i.e what comes out from the mouth of the lord. The teaching of lord mahavira compiled by his disciples in 12 parts called angas. These deal with code of conduct for jain monk, and also expound the jain doctrines in a comprehensive manner.

Question 2.

Triptikas…?

Answer:

The triptikas are the most important literary works of the buddhists. The word triptikas means three baskets of buddhists canon.

name :

3. The vinaya pitaka.

4. The suta pitaka.

5. The abhidhamma pitaka.

Question 3. Causes … rise.

Answer:

5. The rigid caste system.

6. Monopoly of priest for expensive rituals.

7. Difficulty of the common people to understand Sanskrit language.

8. Role of kshatriya princes.

Question 4.

Who was………. His name?

Answer:

Vardhaman Mahavira was the 24th and the last of the tirthankaras.

His father held a prosperous kingdom at his birth time, so he was called vardhamana which meant prosperity.

Question 5.

Five vows….

Answer.

4. Ahimsa - non violence.

5. Asateya - not to steal.

6. Satya - not to tell a lie.

7. Aparigraha - not to possess propoerty.

8. Brahamcharya- to practise chastity.

Question 6.

Tri ratnas.

Answer: according to mahavira, there were three ways to attain moksha, known as tri ratnas ie.

1. Right faith.

2. Right knowledge

3. Right conduct.

Question 7.

Causes…. Jainism.

answer:

1. The use of simple dialect that is prakrit for preaching.

2. The solid patronage by great kings.

Question 8

Two sects…..

Answer:

The two sects of jainism were as follows:

1. Shvetambaras.

2. digambaras.

Question 9

Gautam buddha… born?

Answer:

Gautam buddha was the founder of buddhism. He belonged to the kashatriya clan of sakya. He was born in 563 BC at lumbini near kapilavastu.

Question 10.

What are ……...sights?

Answer:

1. An old man bent with age

2. A sick man groaning with pain.

3. A dead body of man being carried .

4. An ascetic in search of salvation.

Question 11.

When and ……….. Enlightenment?

Answer:

After leaving home in search of truth, gautama wandered from place to place. Afterwards he studied under renowned teachers of rajgriha and at last he went to gaya and practised severe penance and life of austerity and finally at the age of thirty five was enlightened sitting under a peepal tree that place is known as bodh gaya in bihar.

Question 12.

Noble truths ….

Answer:

1. The world is full of suffering.

2. The suffering has a cause.

3. Desire is the cause of suffering

4. If desire is stopped, suffering can also be stopped.

Question 13.

Four points……….buddha.

Answer:

1. Right action

2. Right thought

3. Right belief

4. Right living.

Question 14

Meaning ...name

Answer:
Buddha: gautama after attaining knowledge came to be known as buddha means the enlightened one.

Tathagat: buddha is also called tathagat means the founder of the truth.

Question 15.

Two principles……..sangha.

Answer:

1. To speak the truth.

2. To abide by brahmacharya.

Question 16.

Features of buddhism…

Answer:

1. Buddha inspired the people to lead a simple life.

2. He used simple language.

3. Easy to follow no complex rituals.

Question 17.

difference …. Hinyana and mahayana.

Answer:

Hinyana

Mahayana

Buddha was regarded as human being who attained enlightenment through own efforts

Buddha was regarded as the incarnation of god and provider of salvation

It shuns idol- worship, buddha was not believed as god

The image of buddha was worshipped

Question 18.

Give ….causes of ….

Answer:

1. Division of Buddhism into two sects.

2. Corruption in sungha.

3. Monks and nuns started living worldly lives.

Class 9 Geography

CHAPTER-ROCK STRUCTURE [4]

Ans 1:Lithosphere is the solid crust of rocks on the surface of the earth on which we live.

Ans 2: The continental layer and oceanic layer are the two layers of the lithosphere.

Ans 3: Mantle lies below the crust. Its exact position is between the lithosphere and the core of the earth.This layer is also known as Mesosphere.

Ans 4: Mantle is the second layer of the earth between the crust and the core with its upper boundary marked by Mohorovicic Discountinuity and its lower boundary marked by the Gutenburg Discountinuity.

Ans 5:Core is the central part of earth below a depth of 2900 km. It is also known as Barysphere.

Ans 6: Sial layer is composed of silica [Si] and aluminium [Al]. Therefore it is known as the layer of sial.

Ans 7: PROPERTIES OF CORE OF THE EARTH:

[1]Core the inner most layer of the earth.

[2] It is composed mainly of iron and nickel.

[3]It is the thickest part of the earth and divided into two parts outer core and inner core.

Ans 8 earth is composed of three parts crust , mental and core.

Ans 9 Core is composed of iron and nickel and is called nife.

Ans 10 The temperature increase as we go down due to the gas and pressure present inside the surface of the earth.

Ans 11 The difference between sial and sima.

SIAL [1]Upper most layer of the earth crust.

[2]Its thickness is nearly 20km.

[3]It is composed of silica and aluminium.

SIMA [1]Lower part of the crust.

[2]Its average thickness is about 25 to 30 km.

[3] It is composed of silica and magnesium.

Ans 12 : The two most important and abundant chemical elements present in the earth crust are oxygen 46% and silicon 28%.

Ans 13 : The contacts zone of the crust and mantle is called Mohorovicic Discontinuity.

Ans 14 : Mantle is composed of magnesium and iron silicates along with substantial quantities of sulphites in the upper mantle and nickel and iron in the lower mantle.

Q-DEFINES THE FOLLOWING TERMS:-

[1] Crust-Earths outer shell of crystalline surface rock, ranging from 5-60 km in thickness from oceanic crust to mountain ranges.

[2] Mantle- It is a layer of silicate rock between the crust and the outer core.

[3] Core- The central part of the earth below a depth of 2900 km .

[4] Nife- Core is composed of iron and nickel and is called nife.

CHAPTER- 3
Rotation and Revalution

Ans no.1= The earth is tilted on Its axis. This tilting of the earth on its axis is know as the inclination of the earth axis .

Ans no.2= Coriolis Force.

Ans no.3 = .The rotation of the Earth from west to east determines the direction in which the sun moon and stars appear to rise and set.
.Another proof of rotation of earh is that if one drops a stone from top of a multistorey building it will fall slightly towards the east.

Ans no.4 = Centrifugal force causes slight flattening of the earth at two polls .

Ans no.5 = The spinning of the earth on its polar axis is termed as rotation.
. Effect of Rotation
. The daily occurrences of the day and night.
. The apparent movement of the celestial bodies.

Ans no.6 = Meaning of the term solstice and Equinoxes
solstice : An event occurring when the sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere.
. Equinoxes : The time when the sun crosses the plane of the earths equator makng night and day of equal length all over the earth.

Ans no .7 = Rotation causes the formation of day and night . [Diagram on page no. 33 figure 3.2].

Ans no . 8 = Summer solstice on june 21, winter sostice on december 22 After the spring equinox the sun appears to move north and is directly overhead tropic of cancer on june 21 this is term as summer solstice
. On dec 22 the sun shines overhead on tropic of capricorn in southern hemisphere. The northern hemisphere has its winter solstices .

Ans no .9 = Dec 22 is the longest day in the southern hemisphere .

Ans no. 10 = June 21 is the longest day in the northern hemisphere.

Ans no. 11 = Orbit is the path along which the earth travels when moving around the sun in 365 ¼ days.

Ans no. 12 = The arctic circle experience mid night sun on june 21.

Ans no. 13 = Earth compete one circle around the sun 365 ¼ days. Every four years the extra one-fourth day is taken as one whole day.

Ans no. 14 = Days and nights of equal duration on the equator on 21 march and 23 september.

Ans no . 15 = If axix was perpendicular to the place of ecliptic, every place on the earth surface would have had 12hrs of day and 12hrs of night and there would have been no seasons. [Draw figure no 3.5]

Ans no. 16 = The period of rotation or the time required for the earth to turn through 360 degree is 23hrs , 56minutes ,4.09sec . This period is termed as sidereal day.

Ans no. 17 = The earth is said to be in perihelion on January 3^rd when distance least or about 147million km

Ans no.18= The speed of earth revolution varies according to the path of the orbit occupied .The velocity is greatest at perihelion and least at aphelion

Ans no. 19= The effect of speed of earth rotation are-

.The daily occurrences ofday and night.

.The apparent movement of the celestial bodies

Ans no.20= The two features of summer solstice are –

.The duration of day is longer than night.

.The length of day increases with increasing latitude north of the equator.

Ans no .21= The two motions of the earth are rotation and revolution

Ans no.22= The path along which the earth travel when moving round the sun.

Ans no. 23= The earth rotates on an imaginary line called axis but it is not at right angle to the plane of revolution it make an of 66 1/2degree with the plane of ecliptic andis tilted 23 1/2degree from a line perpendicular to that palne.

Ans no.24= SAME AS ANSWER NO 3.

Ans no.25=The time when the sun crosses the plane of the earth equator making night and day of equal length all over the earth.It occurs on march 21 and September 23.

PHYSICAL EDUCATION (9th Class) CHAPTER-1

Very short answers:

:-Support

:-Shape

:-Protection

:-Junction

:-Storehouse

:-Manufacture of RBC

(With explaination)

2. 206 bones. Longest bones Femur (present in thigh) and smallest bone Stapes(present in ears)

3. Page no. 15(Down Right))

4. Page no. 12(Middle Right)

:-Ball and Socket joint(at Shoulder and Hip joint)

:-Hinge joint (at Elbow joint)

:-Pivot joint (at Neck joint)

:-Gliding joint(at Carpals joint)

:-Saddle joint (at Thumb joint)

Match the following:

Sequence: 4, 6, 7, 2, 8, 1, 5, 3, 9

Short answers:

1. Done

2. Done

3. Femur,Tibia,Fibula, Tarsals, Metatarsals and Phalanges

4. Page no. 13(Left side)

:-Long bones

:-Short bones

:-Flat bones

:-Irregular bones

:-Sesamoid bones

:-Cartilaginuous bones

(With explaination)

6. Three types:

:-Immovable or Fibrous joint

:-Slightly Movable or Cartilaginous joint

:-Freely Movable or Synovial joint

(With explaination)

Long answers:

:-Stronger bones

:-Reduces bone injuries

:-Improves ossification

:-More blood supply

:-Faster healing

:-Increases RBC

(With explaination)

2. Done

3. Bone(same diagram)

Cartilage (Cartilages are elastic hard connective tissues. The elasticity is due to the presence of chondrin protein and some in organic salts. Cartilage has lacunae and chondroblasts in its structure. It is of three types i.e Hyaline, Fibrous and Calcified Cartilage.

4. Done

CHAPTER-2

Very short answers:

:- Provide proper shape and structure

:- Provide effort

:- Bring external movement

:-Help in fluid movement

:- Forceful actions

:- Provide protection

(With explaination)

2. Trapezius, Levator Scapulae and Deltoid

:- Skeletal Muscles

:- Smooth Muscles

:- Cardiac Muscles

(With explaination)

4. Page no. 22

:- Isometric exercises

:- Isotonic exercises (Concentric and Eccentric exercises)

:- Isokinetic exercises

(With explaination)

Match the following:

Sequence:

2, 7, 4, 1, 3, 8, 6, 5, 9

short answers:

1. Done

2. Each muscle is made up of thousands of long and narrow muscle cells called muscle fibres. These muscle fibres are arranged in bundles and enclosed within a tough layer of connective tissue called Epimysium(Sarcolemma).

Every muscle fibres is made up of a very large number of microscopic threads called Myofibrils. Each Myofibril consists of rows of minute protein molecules (Actin and Myosin). It is shaped like two combs with their teeth interlocked at the ends.

3. Page no. 24(any six with their functions)

Isometric Exercises (same length of muscles,no visible movement of muscles,no external movements, work done is zero)

Isotonic Exercises (same tension in muscles, visible movement of muscles, external movement, work is done during these exercises)

5. Done

Long answers:

:- Gain in strength

:- Efficiency improvement

:- Lactic acid tolerance

:- Proper shape of body

:- Faster recovery from injury

:- Increase in muscle mass

2. Done

3. Done in short answers

4. Done

5. Done

FOOTBALL(2nd Term)

(a)It is the most common skill used to hit the ball with power. It reaches long away to the desired position. It is performed in various ways like kicking with inside or outside of foot, instep kick,punt kick, scissor kick, banana or chip kick,roll back kick etc. It can be used during free kick, goal kick, corner kick, penalty kick or when situation suits.

(b) Usually an attacker heads the ball to redirect it towards the net. A defender heads the ball to deflect it away from the goal. In this forehead hits the overhead coming ball.

(c) This skill is used to throw the ball back for the play from the side or touch line. The player must throw the ball over the head while both the feet should be in contact with ground. The player must not touch the sideline during throw in.

(d) During a knock-out tournament, it there is a tie at the end of regulation time then the teams play for 30 minutes extra time of two half of 15 minutes each overtime period. If there is a tie after the overtime period, a penalty shoot-out takes place. Each team chooses 5 players to take the kicks in turns. If the teams are still tied after 5 kicks each, the team keep taking penalty kicks until one team wins. This procedure is called Sudden-Death.

(e)During a knock-out tournament, it there is a tie at the end of regulation time then the teams play for 30 minutes extra time of two half of 15 minutes each overtime period. In this duration if any team makes the goal, wins the match. Earlier there was golden goal period in which the team who scores the goal first wins the game but now it is said as silver goal period.

(f)It is given when referee shows the warning card to the player. In this foul has been committed outside the penalty area like intentional hit to the player, intentional handling the ball, charging, dangerous play, holding opponent from behind, violent play, kicking the opponent. While taking direct free kick the opposing player should be at least 10 yards away from the ball. Goal can be scored from direct free kick.

(g)It is also known as flag kick. Corner kick is awarded when a defender puts the ball out of the play behind his team's goal line. An attacking player then tries to send the ball in front of the goal for another attacker to head or make a short pass to a teammate to convert it into goal. It is taken from corner arc or quarter yard circle.

(h)A penalty kick is awarded when a foul is committed by a defender in the penalty area. The ball is placed on the penalty spot and the attacking player tries to kick it directly into the goal and goalkeeper only defends it. The offences (fouls) are like intentional hit to the player, intentional handling the ball, charging opponent, holding opponent from behind etc.

(i) Player is expelled if he commits a serious foul like strikes or charges or kicks or attempts to kick it trips on opponent, holds opponent, handles the ball intentionally, uses abusive or offensive or insulting language, receives a second yellow card during the game.

(j)A pass between defenders into the open space between the fullbacks and the goalkeeper with the idea that a forward will beat the defenders to the ball. There are two types : a Straight Through Pass and a Diagonal Through Pass.

(k) Done (same as free kick)

(l) Corner arc is also known as quarter yard circle from where corner kick is taken. It is on all four corners. The dimension is 1 yard(91cms)

(m)It is starting the game (in beginning or after half-time or after the goal has been scored or in extra time). During kick-off players remain in their own half. Opponent team player doesn't enter 10 yards circle until ball is pushed or kicked forward. Kick-off player should not touch the ball consecutively second time until played by another player.

(n) The time which game has been stopped temporarily due to injury of the player. This stopped duration of game is added in regular time after each half.

(o)A kick in which the ball is placed on the ground before kicking eg. Penalty kick, Corner kick, Kick-off etc.

(p)The penalty area(outer box) is 18 yards deep, so the ball is only 6 yards from the top of the penalty area. Therefore, the arc(outer circle) is drawn so that all players must be 10 yards away from the ball at the taking of a penalty kick. Also an arc with 9.15m radius drawn outside the penalty area box.

(q) Federation International de Football Association, formed in 1904.

2. Draw Football playfield with all the dimensions from book.

Positions:

Left forward-Center Forward-Right Forward

Left Mid Fielder-Center Mid Fielder-Right Mid Fielder

Left Full Back-Center Full Back-Right Full Back

Goalkeeper

Goalpost (8yard * 8feet with 5 inches thickness of post)

Goal Area(6yards * 20 yards)

4. Done

5. 30 minutes extra time, divided into two halves of 15-15 minutes each.

Direct Free kick

Indirect free kick

Corner kick

Penalty kick

Kick-off

(With explaination)

7. In India, the Britishers brought this game and formed Football Association in 1878. Football became very popular in Bengal. Many clubs were established to improve Football from Bengal. India had started the second oldest Football tournament known as Durand Cup in 1888 from Shimla. Later, this venue was changed to New Delhi from 1940. There are many clubs associated with Football in India like Mohan Bagan, Mohammedan Sporting, East Bengal, JCT, Salgaokar, Mahindra and Mahindra etc.

FIFA(Federation International de Football Association) is the controlling body at International level.

8. Many Football clubs are formed for participation in European league, which had hightened the Football standards in Europe. The best Football players of the world play in European league from different Football clubs like Real Madrid, Barcelona, Juventus, Arsenal etc.

9. Player's basic equipments (Jersey with number,Shorts,Long Stockings, Studs, Shin Guard, Gloves for Goalkeeper etc.)

Football specifications (27-28 inches circumference, 14-16 ounce weight, Leather or Rubber or Synthetic made). The air pressure equal to 0.6-1.1 atmosphere.

10. A player is offside when he is close to the opposing goal line without the ball, unless two defenders are between the attacker and the goal line. Offside is given by linesmen by raising red flag. Goal is not considered in that case and opponent is awarded with indirect kick.

11.

Yellow Card fouls (not respecting referees decision, delay the game, argument, unsportsmanlike conduct, if goalkeeper keep the possession of the ball for more than 6 seconds)

Red Card Fouls (strikes or charges or kicks or trips or holds the opponent, handles the ball intentionally, uses abusive or offensive or insulting language)

Fouls are regulated by Match Referee and two Linesmen.

12. When the ball completely crosses the goal line, either in air or grounded, between the goalposts and under the crossbar of goalpost. It must be scored in a fair manner.

13. Any six(Name and Country)

14. Done

15.

Three substitutions

Substitution procedure is already discussed.

16.

Match Referee regulates the time record of game.

Injury Time (The time for which game has been stopped temporarily due to injury of the player. This stopped duration of the game is added in regular time after each half.

17. Any three(with their name and year)

18. Syed Naeemuddin

19. During a knock-out tournament, it there is a tie at the end of regulation time then the teams play for 30 minutes extra time of two half of 15 minutes each overtime period. If there is a tie after the overtime period, a penalty shoot-out takes place. Each team chooses 5 players to take the kicks in turns. If the teams are still tied after 5 kicks each, the team keep taking penalty kicks until one team wins. This procedure is called Sudden-Death.

20.

Yellow Card fouls (not respecting referees decision, delay the game, argument, unsportsmanlike conduct, if goalkeeper keep the possession of the ball for more than 6 seconds). Yellow Card is a warning card.

Red Card Fouls (strikes or charges or kicks or trips or holds the opponent, handles the ball intentionally, uses abusive or offensive or insulting language). Red card is an expulsion card. To whom it is shown can not play further in the same match. Also,under such condition substitution can not be done.

21.

-Unsupportive Behaviour

-Abusive words or action

-Delays the restart of game

-Enters in playfield without permission of Referee

-Leaves playfield without permission of Referee

-Infringes the laws of game

22. Red Card

23. Yellow Card

24.

Fouls (kicking or Trips or Holds an opponent)

Offences (Deliberately Delays game, infringement of rules, argumentative behaviour)

25.

Trapping the ball by Chest,Thigh and under the feet.

26.

Dropped Ball(In case of struggle for ball possession when both players commit simultaneously foul, in that case the Referee stops the game for some time and afterwards drops the common ball to get the possession of the ball. Play restarts when ball touches the ground.

Heading (An attacker heads the ball to redirect it towards the net. A defender heads the ball to deflect it away from the goal. In this forehead hits the overhead coming ball.

27. Done

28. Done

29. Done

30.

-The Ball(at penalty spot, i.e 11m from goal line)

-The Defending Goalkeeper (In front of goal line,in own goal area)

The Players (Behind the outer circle, i.e arc drawn outside the penalty area box)

31. Done

32.

(a)110m and 75m

(b)90 minutes for men

80 minutes for women

Extra time (30 minutes divided into two halves of 15-15 minutes each)

(c)

8 yards and 8 feet

(d)

10 yards and 1 yard

VOLLEYBALL

(a)A specialized defensive player who plays in rear half to provide rest to certain Player. He can be substituted anytime during match from rear row player. He wears different colour kit. He can not serve, block and smash (he can smash behind the attack line)

(b)After every change of service, the players of serving side rotate in clockwise direction, otherwise, it may be a foul.

(c)In Tennis Service, the server can stand anywhere behind the 9m see line and executes it as a spike behind the service line. If it is hit well, the serve is a powerful offensive skill.

(d) It is a powerful attack. It has variations like back court spike, line shot, cross court shot, dip, block abuse, off-speed hit, slide, double quick hit etc. Player who executes the spike have an excellent sense of balance in the air and can perceive and anticipate the actions and positions of the opposing team members. Contact with the ball takes place above the net. A player specialized in smash is known as spiker.

(e)It is a rally technique used during the match. The tip is a transitory move between reception and attack like overhead set. It is made with an upward movement of the arms and legs. Contact with the ball is with the fingertips without touching palm. A player specialized in lifting is known as Booster or Setter.

(f)Bump is a defensive skill keeping the ball from falling, receiving serve and offensive skill as it provides good chance to tip the ball for the spiker. Bump is the first contact of the ball (service reception). The bump provides the transition between defence and attack.

(g)It may be executed by one, two or three players and it is the first line of defence against the spike. Blockers are not expected to block all spikes but to do as a screen, reducing the floor space that must be covered by the players behind them. To block, a player has good anticipation of the play. The tallest players are usually the main blockers.

(h)A ball hit into the net, by a team may still be kept in play (up to 3 hits) provided that the net is not touched by a player. Players may not touch the net. If 2 opposing players touch the net simultaneously, the ball is declared dead and is replayed. Also when the ball touches the hand of blocking players during smash and fall outside the court.

(i)A player specialized to hit the ball down towards the opponent's court. He is also known as smasher.

(j)A player specialized to lift the ball for the smash. It is performed over the coming ball from own teammates. This player is also known as Booster.

(k) During service the players must stay in their positions i.e diagonally opposite player must be in the same manner as in beginning. Otherwise, positional fault is given to opponent.

(l)A hit aimed at opponent's court as to gain a point and a service in form of spike,dig,dink etc.

(m)A player of servicing team must not prevent the visibility of service player (server). The collective screening, from seeing the server or the flight path of the ball is illegal.

(n)An extended upright over the net which gives the idea of sideline. It is 180cm in length whereas 80cm above the net. It is made up of fibreglass, flexible in nature.

(o)An extended line behind the center line which restricts libero to smash from front area of court. It is 3m away from the net.

(p)An area behind the backline which is used for performing service. It extends 3-5m behind the service line.

(q)It is given for 60 seconds in the final set when leading team reaches the 8th and 16th points. It may be requested by each team.

(r)It is temporarily interruption asked by the coach during game. Each team may request a maximum of two timeouts. All requested timeouts last for 30 seconds.

(s)A fault in which a wrong positional player performs the service.

(t)A fault given when the opponent player enters into the opponent area in air, by crossing center line by foot or by hands over the net during smash, block or lift.

(u)A player when takes the support from teammate or any other structure or object in order to reach the ball within the playing area.

2. The game of Volleyball, originally called "Mintonette" was invented in 1895 by William.G.Morgan after the invention of Basketball. Volleyball rules were framed in 1928 by United States Volleyball Association (USVBA). IN 1947, the Federation International de Volleyball (FIVB) was founded in Paris. It was included in the 1964 Olympic Games. In India, Volleyball came into Vogue through YMCA and later Volleyball Federation of India (VFI) was formed in 1950.

:- One team have total 12 players (6 playing and 6 substitutes)

:- The team that wins a rally, wins a point and a service.

:- A set is won by scoring 25 points.

Net(size of net : 9.5m * 1m width, height of net : 2.43m for men and 2.24m for women)

Ball(circumference of ball : 65-67cm, weight of ball : 270gm)

Antenna(Done)

5. Replacement of one or more players from the listed substitution apart from libero. The coach requests for substitution to the assistant referee. An area 3m away towards sideline is allowed to move for substitution. When referee signals for substitution the player should move out and substitute player should enter. There are two types of substitutions, legal and illegal substitution.

6. There are lots of variations of service like underhand,top spin, floating,jump,jump float, round arm, tennis service etc.

Lift(Done in question 1 (e) part)

Bump(Done in question 1 (f) part)

8. The advantage of block is to stop the spike/smash,so that ball should fall in opponent court and to gain a point and a service.

It is performed by front row tall player/players, either one,two or all three players together. They takes vertical jump with their arms stretched up in the air and open palms on the way of spike trajectory.

:- Net touch

:- over the net penetration

:- under the net penetration

:- body contact with opponent

:- if a back row player blocks

:- if libero blocks

9. When there is a tie at 24-24 points each, the game is extended for two points because to win a set one team should have a lead of 2 points.

10. From book with all dimensions

11. After every change in service, the players of the serving side rotate in clockwise direction so that each player should get equal chance to play in front and back zone both except Libero.

Positional fault (Done)

12.

Attack line(Done)

Back line (A line at the back of court at 9m from the net. It is also known as service line.

13.A free zone area on both the sides of court, which extends up to 3m, where player of both the teams performs warming-up for 3-5 minutes before the start of the match.

14. 3 contacts

15.

Set(A set is won by a score of 25 points. And if there is a tie at 24 points then game continues until one team has a two points lead)

Match(A match is won by winning 3 sets out of 5)

16. Done

17.

Legal substitution (same as substitution-already discussed)

Illegal substitution (Each team can do 6 substitutions in a set. In case, if there is injury or expulsion and team has already completed their 6 substitutions in a set, under such condition the substitution done is known as illegal substitution. A team who ask for it, is penalized. A point and a service is awarded to the opposing team.

18. Done

19.

First Referee (Regulates the rules, starts and ends the match, Whistles,gives violations, fouls and penalties)

Assistant Referee (Gives rotation fault, positional fault and line cut)

Captain (Performs toss, give positions to players, ask time outs and substitutions from Referee, with the consent of coach)

20. Any six

21. Beach volleyball is played on a Sandy surface. Only two players on either side plays at once. FIVB added it in world championship series in 1987 and later in 1996 it was added to the Olympics.

22. Done

23. Rotation fault, penetration fault, positional fault,net touch, service line cut during service and 8 seconds service delay violation.

24. Time outs, Intervals after each set, Objections, Instructions by officials, legal substitution, illegal substitution, ball out of play etc. Also due to violations,fouls, exchange of words between players, physical fights,Bad or poor lights, equipments failure,poor playing surface,team arrives late at venue etc.

25.

Penalty (Yellow Card) : deliberately delaying of the game, provoking opponent by words or actions etc.

Expulsion (Red Card) : Use of abusive language, Physical fight etc.

Disqualification (Red and Yellow Cards jointly) : Shouting on referee from bench area, disturbing table & court officials etc.

26. If match is of league tournament then equal points will be shared by both the teams. And if match is of knock-out tournament then match can be restarted after interruption if possible. Else, match can be resumed from the same points on the kept spare day. Otherwise can be played from beginning on some other selected day.

27.

Sanctions imposed by Referee:

Warning : Verbal warning,

Penalty : Yellow Card,

Expulsion : Red Card,

Disqualification : Red and Yellow Cards jointly.

28. Net fault (when ball stuck in net during service), service line cut by server, screening, ball lands out of bounds, Rotation fault and Positional fault.

29. Done(24)

30. Done(26)

31. Signals out(when ball lands out of court), signals in(when ball lands in the court), judgement of side with the help of the Antenna.

32. Done

33. Two white side bands are fastened vertically to the net and placed directly above each sideline. They are 5cm wide and 1m long and are considered as part of the net. They are elastic in nature.

BADMINTON

1. (a)It is delivery of the shuttle to opponent court to begin with rally.

(b) This is an offensive as well as defensive stroke. It is taken with overhead swing of the racket to hit the shuttle hard so that it goes deep and back in the opponent's court. It may be high clear or low clear, over the both sides of the court in opponent's side.

(c)This is an offensive stroke to stop the rally at once. In this, shuttle is powerfully hit in downward direction and gives no chance to the opponent to return. Shuttle is hit with very fast swing of hand just over the head. Shuttle goes steep down in opponent's court.

(d) During service both the feet should be stationary, otherwise, it is a fault.

(e)It is the way of scoring in the beginning i.e the score is zero at both sides.

(f)A game(setting) consists of 21 points continuous scoring, in the best of three games(sets).

(g)An area between the back boundary lines and long service line for doubles. It is the back area of the court where long service is considered out during doubles game, also known as Back Alley.

(h)It is the continuous return of strokes by both the players over the net.

(i)It is the last point in the game by which game winner is decided.

(j)It is playing the strokes from the left side of the body (for right handed player).

(k)It is the redelivery of the same point. It is called by umpire due to unforeseen situations like : umpire is unable to see the landing of shuttle, fault at both sides of the players simultaneously, if receiver is not ready, shuttle breaks during rally etc.

(l) During service the shuttle has to be delivered below the waist level, otherwise, it is a fault.

(m)A variation of forehand stroke in which shuttle is hit hard but at low height.

(n)A shot in which shuttle crosses the net in a diagonal direction.

(o) When score is at 20 all(20 each) on both sides.

2. The modern version of Badminton is said to have its origins in the city of Pune in India and was initially called 'Poona'. British Army officers posted there were the first pioneers of the game who took it to Europe. The game was played in 1873 in a place called 'Badminton House' in England, from where it got its name.

3. Draw Badminton court and give all dimensions from book.

4. 5 feet at the center and 5 feet 1 inch near the poles.

5. Player/Team, whoever wins the rally, is awarded with a point and a service. Also, in case of fault done by one player, a point and a service is awarded to the other player.

:- A game consists of 21 points.

:- Continuous point scoring is followed.

:- Change of sides are done after each game and also on the 11th point in the final game.

:- Clear(explain)

:- Smash (explain)

:- Drive (explain)

Already done in question(1)

8. In case of tie at 20th point, the difference of two points will be considered for deciding game.

9. Service is performed diagonally i.e. from right to right and left to left side over the net as to begin the rally.

Service is illegal, if it is delivered from above the waist level, both feet are not stationary at the time of service, delivered from wrong side of the court and wrong player delivers the service.

10. In doubles game a team of two players each plays against the other. They begin the game with the service from right side of the court to right side opponent player(diagonally). A game consists of 21 continuous points. A team who wins a rally is awarded with a point and a service. After winning a rally, teammates changes their sides i.e. right side player goes to left side and left side player to right side(opponents will not change their positions, until they wins a point on their service). Same player serves as long as he is winning continuous points.

11.

Drop(An offensive stroke hit from deep end which lands close to net)

Smash (Done)

12. Done

13. To check condition of playing surface, conducting toss, to call out score after end of each rally, to check flight of shuttle in case of dispute, to give break for cleaning sweat and to sit on high bench to observe the match carefully.

14. To check waist fault, foot fault, line cut, service court error, changes shuttle on demand of player, cleans sweat in case falling over the court and sits opposite to Umpire at normal height.

15. arming-up exercises (shuttle run, squats, sit ups, push ups, stretching, skipping, zig-zag running etc.)

Conditioning exercises (lunges, s

CLASS 9 BIOLOGY

Chapter 2 - Cell: The Unit Of Life

Question 1

1. Which one of the following cell organelles is correctly matched with its function?

(a) Ribosomes Synthesis of proteins

(b) Mitochondria Secretion of enzymes

(d) Centrosome Carries genes

2. All life starts as

(a) an egg

(b) a single cell

(d) a chromosome

3. Which one of the following is found both in the cells of a mango plant and a monkey?

(a) chloroplasts

(b) centrioles

(d) cell membrane

4. A plant cell can be identified from an animal cell by the

(a) absence of centrosome

(b) presence of cell membrane

(d) none of the above

5. Plant cell has a cell wall made of

(a) Protein

(b) Fructose

(d) Fatty acids

6. The cell organelle that helps in respiration of the cell is

(a) Mitochondria

(b) Lysosome

(d) Centrosome

SOLUTION 1

1. (a) Ribosomes Synthesis of proteins

2. (b) a single cell

3. (d) cell membrane

4. (a) absence of centrosome

5. (c) Cellulose

6. (a) Mitochondria

Question 2

Name the part of the cell concerned with the following.

(a) Liberation of energy

(b) Synthesis of proteins

(d) Initiation of cell division

(e) Hydrolytic in function

(f) Entry of only certain substances into and out of the cell

SOLUTION 2

(a) Mitochondria

(b) Ribosomes

(d) Centrosome

(e) Lysosomes

(f) Cell membrane

Question 3

State whether the following statements are true (T) or false (F):

(a) All animal cells contain a cell wall. T/F

(b) A cell wall is made up of protein. T/F

(d) Plant cells contain large vacuoles. T/F

(e) Protoplasm is the part of the cell which surrounds the nucelus. T/F

(f) Genes are located in chromosomes. T/F

(g) Anthocyanins are the pigments of flowers, which are dissolved in cell-sap. T/F

SOLUTION 3

(a) F (False). Animal cells do not contain a cell wall.

(b) F (False). A cell wall is made up of cellulose.

(d) T (True)

(e) F (False). In eukaryotes, cytoplasm is the part of the cell which surrounds the nucleus.

(f) T (True)

(g) T (True)

Question 4

How many chromosome pairs are found in human cells?

SOLUTION 4

23 pairs of chromosomes are found in human cells.

Question 5

What is the name of the chemical substance which constitutes the genes?

SOLUTION 5

DNA (Deoxyribonucleic acid)

Question 6

Match the items in column 'A' with those in column 'B'

Column A	Column B
(a) Vacuoles	(i) Intracellular digestion
(b) Nucleolus	(ii) Respiratory enzymes
(c) Lysosomes	(iii) Covered by tonoplast
(d) Anthocyanin	(iv) Dissolved in the cytoplasm
(e) Cristae	(v) Forms RNA

SOLUTION 6

Column A	Column B
(a) Vacuoles	(iii) Covered by tonoplast
(b) Nucleolus	(v) Forms RNA
(c) Lysosomes	(i) Intracellular digestion
(d) Anthocyanin	(iv) Dissolved in the cytoplasm
(e) Cristae	(ii) Respiratory enzymes

Question 7

Fill in the blanks:

(a) _________ consists of membranous sacs and secretes 40 types of digestive enzymes.

(b) _________ is surrounded by microtubules, located near the nucleus.

(d) More than 1000 chromosomes are found in the nucleus of certain

(e) _________ are hereditary units.

(f) _________ is a plastid which stores starch.

SOLUTION 7

(a) Lysosome

(b) Centriole

(d) Insects

(e) Genes

(f) Leucoplast

Question 8

It is said that the protoplasm cannot be analysed chemically. Why?

SOLUTION 8

Protoplasm is the living matter of the cell. Protoplasm cannot be analysed chemically because the chemical composition of protoplasm is very complex. It varies slightly from one cell to another, although the common elements included in the composition of protoplasm such as carbon, hydrogen, oxygen, nitrogen, sulphur, iron and phosphorus are still the same in all the cells.

Question 9

What is the difference between an organ and an organelle?

SOLUTION 9

Organs of an organism are the parts of the body which have a definite shape and structure and perform specific functions. Cell organelles are also parts of the cell which have a definite shape and structure and perform specific functions. Organelles have the same status in a cell as the organs have in the entire body of an animal or a plant performing specific functions.

Question 10

Do you think the cells of an elephant would be larger than the cells of a rat? Explain briefly.

SOLUTION 10

The cells of an elephant would be of the same size as the cells of a rat. The size of cells does not vary within the organisms, however, the number of cells varies from one organism to another. A larger animal like an elephant will have more number of cells as compared to a smaller animal like a rat. However, the size of the cell will be the same.

Question 11

Differentiate between the following pairs of terms:

(a) Protoplasm and cytoplasm

(b) Nucleolus and nucleus

(d) Cell wall and cell membrane

(e) Plant cell and animal cell

(f) Prokaryotes and eukaryotes

SOLUTION 11

(a) Protoplasm and cytoplasm

Protoplasm	Cytoplasm
(i) It is the living matter, the total substance of a living cell, i.e. the cytoplasm and the nucleus.	(ii) It is a mixture of water and soluble organic and inorganic compounds, in which various cell organelles are embedded.

(b) Nucleolus and nucleus

Nucleolus	Nucleus
(i) It is a round-shaped nucleoli present inside the nucleus.	(ii) It is a dense spherical structure present in the cell that contains a network of thread-like structures called chromatin fibres.

Centrosome

Chromosome

(i) It is a clear area of cytoplasm close to the nucleus, from which spindle fibres develop during cell division.

(ii) Centrosome is found only in an animal cell.

(i) Chromosomes carry hereditary information or genes which transmit genetic characters from parents to offspring.

(ii) Chromosomes are found in the nucleus of both, animal and plant cells.

(d) Cell wall and cell membrane

Cell wall	Cell membrane
(i) It is a non-living rigid layer.	(i) It is a living, thin, flexible membrane.
(ii) It is made of cellulose.	(ii) It is made of lipoproteins.
(iii) It is freely permeable.	(iii) It is semi-permeable.

(e) Plant cell and animal cell

Plant cell	Animal cell
(i) Cell wall is present.	(i) Cell wall is absent.
(ii) Centrosome is absent.	(ii) Centrosome is present.
(iii) Vacuoles are large and prominent.	(iii) Vacuoles are small and temporary.
(iv) Plastids are present.	(iv) Plastids are absent.

(f) Prokaryotes and eukaryotes

Prokaryotes	Eukaryotes
(i) Organisms with cells containing a primitive, undefined nucleus are called prokaryotes.	(i) Organisms with cells containing a well-defined nucleus with a nuclear membrane are called eukaryotes.
(ii) They contain small ribosomes.	(ii) They contain larger ribosomes.
(iii) They lack other cell organelles.	(iii) They contain other cell organelles.
(iv) Examples: Bacteria, blue-green algae	(iv) Examples: Euglena, Human beings

Question 12

Mention three features found only in plant cells and one found only in animal cells.

SOLUTION 12

Features found only in plant cells:

(i) Presence of cell wall

(ii) Presence of large vacuoles. The liquid contained in vacuoles is called cell sap

(iii) Presence of plastids

Features found only in animal cells:

(i) Presence of centrosome

Question 13

Why are the cells generally of a small size?

SOLUTION 13

Cells generally remain small in size because:

(i) To enable different regions of the cell to communicate with each other rapidly for the cell to function effectively

(ii) To have a large surface area is to volume ratio for greater diffusion of substances, in and out of the cell

Question 14

What is the cell theory? Who propounded it and when?

SOLUTION 14

Postulates of cell theory:

(i) Cell is the smallest unit of structure of all living things.

(ii) Cell is the unit of function of all living things.

(iii) All cells arise from pre-existing cells.

Cell theory was propounded by Theodor Schwann and Matthias Schleiden in the year 1839 and was modified by Rudolf Virchow in 1858.

Question 15

Mention any three differences between a living cell and a brick in a wall.

SOLUTION 15

Living cell	Brick in a wall
1. Non-rigid living structure	1. Rigid non-living structure
2. Mainly composed of cellulose	2. Mainly composed of soil
3. Freely permeable	3. Impermeable

Question 16

Name the plastid and pigment likely to be found in the cells of

(a) petals of sunflower

(b) ripe tomato

(d) cells of potato

SOLUTION 16

Cells	Plastid	Pigment
(a) petals of sunflower	Chromoplasts	Xanthophyll
(b) ripe tomato	Chromoplasts	Carotene
(c) skin of green mango	Chloroplasts	Chlorophyll
(d) cells of potato	Leucoplasts	No pigment

Question 17

State the major functions of the following:

(a) Plasma membrane

(b) Ribosome

(d) Mitochondria

(e) Golgi apparatus

(f) Cytoplasm

(g) Asters of centrosome

(h) Chromosomes

(i) Glycogen granule

(j) Vacuoles

SOLUTION 17

(a) Plasma membrane:

(1) Separates contents of the cell from its surroundings

(2) Regulates the entry of certain solutes and ions

(3) Maintains the shape of animal cell

(b) Ribosome:

(1) Protein synthesis

(1) Intracellular digestion

(2) Destroy foreign substances

(3) When the cell is old or injured, lysosomes rapidly destroy cell organelles and hence, are called suicide bags.

(d) Mitochondria:

(1) Synthesis of respiratory enzymes

(2) Release of energy from pyruvic acid produced in cytoplasm in the form of ATP

(e) Golgi apparatus:

(1) Synthesis and secretion of enzymes, hormones, etc.

(2) Formation of acrosome of sperm

(f) Cytoplasm:

(1) Different organelles contained in it perform different functions.

(2) All metabolic activities occur in it.

(g) Asters of centrosome:

(1) Initiates and regulates cell division

(2) Forms spindle fibres

(h) Chromosomes:

(1) Carry genetic characters from parents to offspring

(i) Glycogen granule:

(1) Serves as food for the cell

(j) Vacuoles:

(1) Gives turgidity to the cells

(2) Storage of water and other substances, food, pigments and waste products

Question 18

List any six features found both in plant and animal cells.

SOLUTION 18

Common features found in both plant and animal cells:

(1) Presence of cell membrane

(2) Presence of liquid matrix called cytoplasm in the cell

(3) Presence of mitochondria which produces energy

(4) Presence of ribosomes that synthesize proteins

(5) Presence of Golgi body

(6) Presence of a prominent nucleus

Question 19

Given below are the sketches of two types of cells A and B.

(a) Which one of these is a plant cell? Give reason in support of your answer.

(b) List the cell structures which are common to both the types.

SOLUTION 19

(a) Fig. B is a plant cell. It has a cell wall and a large vacuole which pushes the nucleus towards the periphery.

(b) Cell membrane, ribosomes, nucleus, endoplasmic reticulum, lysosomes, Golgi body and mitochondria are common to both the types.

GEOGRAPHY

Earth’s Structure

Exercises

I. Short Answer Questions

Question 1. Name the sources of information about forces operating inside the earth. Answer: Information about forces operating inside the earth is taken by the study of seismic waves, materials thrown up by volcanoes and the evidence from the theories of the origin of the earth.

Question 2. In which part of the earth is NIFE found ? What it is composed of ? Answer: NIFE is found in the inner core of die earth. NIFE is composed of Nickel (Ni) and Iron (Fe), being heavy metals and having high density, these are found deep inside the earth.

Question 3. What are the consequences of the pressure and temperature in the interior of the earth ? Answer: Due to the extreme temperature of 2200° C, every matter is in liquid and gaseous state in the interior core, the temperature in the mantle ranges from 870° C to 2200° C, so things are in semi – liquid to liquid state, the crust, a layer of 60 km, breadth, is made of solid rocks with a density of 2 – 3, g/Cm3. The density goes on increasing to 3-4g/Cm3 in the mantle and 10-13 g/Cm3 in the core.

Question 4. What is the lithosphere ? Answer: The crust is called Lithosphere made of solid rocks with a thickness of 60 km. below high mountains and 6-12 km below the oceans.

Question 5. Name the three layers of the earth’s interior. Answer: The three layers of earth’s interior are:

1. Core 2. Mantle

3. Crust

Question 6. State two chief characteristics of the earth’s crust. Answer: The crust is made of solid rocks and divided into oceans and continents.

Question 7. Describe the mantle. State its two chief characteristics. Answer: Mantle lies between 60 – 2900 km. depth. It is divided into two parts namely upper mantle and lower mantle, which are in the form of solid rocks and semi-molten rocks respectively.

Question 8. Where is asthenosphere found ? In which form does it exist ? Answer: At the depth of 100 – 250 km. The mantle is partially molten and known as asthenosphere, with a temperature of 1100°C.

Question 9. Write one difference between Moho Discontinuity and Gutenberg Discontinuity. Answer: Moho Discontinuity is the boundary between crust and mantle and Gutenberg Discontinuity is the boundary between mantle and core.

Question 10. Why is the earth’s interior in most part found in a solid state despite great heat and pressure ? Answer: The solid state of the inner core is due to high density and pressure which have compressed molten rock material and keep this layer firm and solid in some parts due to high pressure inspite of the temperature of 5000°C.

Question 11. Name two types of earth movements. Answer: Two types of movements are due to isostasy and tectonic plates. Isostasy is the process of natural balance between different landforms and the sliding movement of the tectonic plates of the earth’s crust.

Question 12. What is Geology ? Answer: Geology is the science dealing with the origin and types of rocks found in the interior of the earth.

II. Give reasons for each of the following

Question 1. The study of meteorites helps scientists to know about the interior of the earth. Answer: At the time of the origin of the earth every planet and meteorites were floating in the space and the materials of the earth were same as that of the meteorites. So, the scientists can calculate the composition of rocks ofthe earth by studying the materials found in the meteorites.

Question 2. Temperature starts rising gradually towards the interior of the earth. Answer: Due to enhancing density and pressure the temperature goes on increasing gradually towards inside of the interior of the earth.

Question 3. The asthenosphere is in a semi-molten state. Answer: At the depth of 100 – 250 km the mantle is partially molten and known as asthenosphere due to the temperature around 1100°C along with greater pressure and density.

Question 4. The inner core is in a solid state. Answer: The high pressure in the interior core keeps this layer firm and solid in some parts, in spite of the temperature as high as 5000°C.

Question 5. The continents are placed above the oceans. Answer: The density of continents is lesser than the layer supporting the ocean beds, so the continents came floating upwards at the time of the formation and solidification of the earth, as the lighter things come upwards floating over the heavier things i. e. Sial is lighter than Sima

III. Long Answer Questions

Question 1. Look at the figure on the side and answer the questions:

(a) Label the parts : (1), (2), (3), (4) and (5). (b) Name the state (solid, liquid or gas) in which each part exists.

Answer: (a)

1. Atmosphere 2. Lithosphere 3. Mantle 4. Core 5. Hydrosphere.

(b)

1. Atmosphere — Gas 2. Lithosphere — Solid 3. Mantle — Semi-solid 4. Core — Molten state or liquid 5. Hydrosphere — Liquid (water)

(c) What part is suitable for human habitation? Why? Ans. Outer part of the earth is suitable for human habitation due to favourable conditions for survival, i.e. atmosphere for air, Lithosphere for settlement due to ideal temperature and land, hydrosphere for hydrological cycle for providing rainfall and fresh water bodies on the earth and oceans for navigation and trade routes etc.

Question 2. Describe the layers of the interior of the earth and their chemical composition. Answer: The interior of the earth is divided into three major parts i.e. crust, mantle and core. The crust consists of majority of, silica and aluminium and is called ‘SIAL’, mantle is called SIMA due to the majority of silica and magnesium and is called SIMA, which makes the bed of oceans and the core is called NIFE with excess of Nickel and Iron (Ni + Fe).

Question 3. There are two transitional zones between the two consecutive layers of the interior of the earth. Name them and state their chief characteristics. Answer: The transitional zone between crust and mantle is Moho Discontinuity which is the dividing zone between solid and semi-solid state of rocks due to the increasing temperature as the depth increases. The boundary between mantle and core is known as Gutenberg Discontinuity, below this zone both density and temperature going on increasing. The density is more than 13 and temperature is more than 2200°C.

Question 4. Explain the layers of the interior of the earth with reference to the following :

a) Depth, (b) Temperature (c) Density.

Answer: Crust :

(a) Depth 35-50 km below continents and 6-12 km. below the oceans. (b) Temperature — Less than 870°C (c) Density — 2.7 g/Cm3 – 5.5 g/Cm3.

Mantle :

(a) Depth — 50 – 2900 km. (b) Temperature — 1500° C – 2200°C (c) Density — 3 g/Cm3 – 4.5 g/Cm3

Core :

(a) Depth — 2900 km – 3500 km (b) Temperature — 2200°C – 5000°C (c) Density — 10.0 g/Cm3 – 13.6 g/Cm3.

Question 5. Study the figure on the side and answer the questions:

(a) What is known as Sial ? How deep is the area marked by Sial ? (b) What role does Sima play ? (c) Why is the expression ‘Nife’ so called ? (d) Which layer is responsible for earth’s magnetic field ? Why? (e) What happens to the continents if there is an earthquake?

Answer:

(a) Sial is the upper layer or crust of the earth. The name Sial is based on the excess of Silica and Aluminium. The depth of Sial is 60 km. (b) Sima is the second layer of earth which gives support to the ocean beds. There is the excess of Silica and Magnesium. (c) ‘Nife’ means Nickel (Ni) and Iron (Fe) due to the majority of Nickel and Iron in the core, (d) Core of earth is responsible for earth’s magnetic field because it is composed of iron and nickel which is responsible for earth’s magnetism. Magnetic field is oriented towards North and South Poles. (e) Several drastic changes may occur during the earthquake. It depends on the intensity of the earthquake. If intensity is 8 or more buildings may break up, casualties and major changes on the landforms as broad breaking gaps, origin or disappearing of several small islands.

Practice Questions (Solved)

Question 1. Which are the two most abundant chemical elements in the Earth’s crust ? Answer: Oxygen and Silicon.

Question 2. Why does the Sun not rise at the same time everywhere in the world ? Answer: If the Earth were flat, the whole world would have the sunrise and sunset at the same time. As the Earth is spherical and rotates from West to East, places in the East see the Sun earlier than the places in the West.

Question 3. “The whole of the approaching ship is not visible at one time.” Why ? Answer: The Earth has a spherical snape. Along its curved surface, the appearance of a ship is gradual. We see first the smoke, then the mast and then the hull. If the Earth were flat, the entire ship would be seen all at once.

Question 4. “Even when the Earth is spherical, it appears to be flat.” Discuss. Answer: The actual shape of the Earth is spherical. The curvature of the Earth is small as compared to its big size. For a small area upto 100 sq. miles, this curvature is negligible. Therefore, it appears flat.

Question 5. Why is the Earth slightly flattened at the poles ? Answer: The Earth is not a perfect sphere. It is slightly flattened at both the poles. It is due to the centripetal force produced by the rotation of the Earth.

Question 6. Explain briefly the structure of the earth. OR Discuss the structure of the earth giving details about each of its layers and arguments in support of your contention. Answer: The structure of the earth means the interior of the earth. The entire earth is composed of three zones

1. Lithosphere 2. Mesosphere and 3. Barysphere.

(i) The Crust or Lithosphere It is the outermost layer. Its thickness varies from 8 to 60 kms. It is solid and is formed largely of igneous rocks. The crust consists of two layers.

1. a lower, continuous layer of basaltic (mafic) rocks and 2. and upper layer of granitic (felsic) rock, which constitutes bulk of continents. It is absent in ocean basins. These parts of the crust forming the continents are much thicker than the crust under the oceans. Its main universal constituents are Silica and Aluminium. It is collectively known as ‘SIAL’. It has an average density of 2.7. The lower layer has an average density of 3.0. It main mineral constituents are

Silica (SI) and Magnesium (MA) and is therefore called ‘SIMA’. Since the SIAL is lighter than the SIMA, the continents can be said to be floating on the layer of denser SIMA.

(ii) Mantle or The Mesosphere Beneath the crust or Lithosphere lies the Mantle or Mesosphere. Its thickness is 2840 km. Its density is 3.1 to 5.0. It depth is 2900 km. It is again divided into two sub layers.

1. the internal Silicate layer (SIMA). Its thickness is 1140 km and density varies from 3.1 to 4.75 and 2. Mixed layer of metals and silicates. Its thickness is 1700 kms. and density is 4.75 – 5.0.

(iii) Core or the Barysphere It is the central nucleus. It is made up of dense rock materials – Nickel and Iron. It is also called the layer ‘NIFE’. Its thickness is 3471 km (radius of core). It is again divided into two sub-layer

1. The outer core is liquid or plastic in nature and 2. Inner core (Barysphere) which is solid and rigid because of tremendous overlying pressure. The density of core is 5.1 to 13.

Question 7. Where is Mantle located in the Earth ? Answer: The Mantle or Mesosphere is located between 2850 – 2900 km beneath the earth crust.

Question 8. Describe any three experiments to prove the Spherical Shape of the Earth. Answer:

1. If you observe a ship approaching sea coast, the top of the mast is seen first and the hull, lower parts are seen gradually. Due to the curvature of the Earth, the whole ship is not seen at one time.

2. Fix three poles of equal length at equal distance on the ground. These do not give a horizontal level. The top of the middle pole looks higher than the other two poles due to the curvature pf the Earth. This experiment was done by Mr A.R. Wallace

on Bedford canal.

3. If you look around at the Earth’s horizon (where Earth and sky appear to meet), it will everywhere and always appear circular. It widens with increasing altitude due to Spherical Earth.

Biology standard 9. Chapter 4(The Flower)

A. MULTIPLE CHOICE TYPE

1. Bougainvillea flower is an example of

Ans(d). large colourful bracts

2. A flower is said to be complete when:

Ans(d). It has all the four whorls.

3. The part of the flower that gives rise to the fruit is

Ans(c). Ovary

4. The part of flower that gives rise to seed is

Ans(c). Ovule

5. The essential whorls of a flower are the

Ans(d). Androecium n gynoecium

B. Very short Answer type

1. Match

(a) Polyadelphous—— bombax

(b) pollen grain—— pollen sac

(d) Non-essential—— calyx,corolla

(e) sweet fragrant fluid—— nectar

C. Short Answer Type

1. Explain

(a) Incomplete Flower

Ans. If one or more sets of floral structures are missing, the flower is called incomplete.

(b) Staminate flower

Ans. A unisexual flower which contains only the stamens is called Staminate flower .

Ans. The flower which contains only the carpels is called pistillate flower.

(d) Bisexual Flower

Ans. A flower which contains both stamens and carpels is called bisexual flower.

3. Where are following structures/parts located and their function

(a) placenta—- ovary

Function—- attach ovule to the wall of ovary

(b) Thalamus—- tip of flower stalk

Function—- attach flower to the stalk

Function— contains pollen grains

(d) Stigma—- Carpel

Function—- landing place for pollen grain

4. Why are the following described as stated:

(a). The androceium of pea flower is diadelphous because filaments are united in two bundles

(b). Ray florets of sunflower as neuters because both male and female reproductive organs are lacking.

(C). Salvia sepals are petaloids because perianth is non green.

D. Long Answer Type

Ans(a). 1. Monadelphous: Stamen are united in one group by their filament. E.g. china rose

2. Diadelphous: The filaments are united in two bundles. E.g. pea

3. Polyadelphous: the filaments are united in several groups. E.g. bombax

Ans(b). (a) China rose—- Monadelphous

(b) Bombax—- Polyadelphous

ote : these questions will include an inside portion.

Class 9

History and Civics

Chapter 1 of civics

Question 1:

What is meant by the term constitution

Answer:

Question 2:

On the basis of which plan was the constituent assembly constituted?

Answer:

Cabinet mission plan.

Question 3

What is objective resolution?

Answer:

Objective resolution was proposed by pt. Jawahar lal nehru on december 13, 1946 for highlighting the national goals.

Question 4;

By whom was the objective resolution proposed?

Answer:

It was proposed by the Pt. Jawahar Lal Nehru.

Question 5:

Who was appointed as the chairman of the drafting committee of the constitution?

Answer

Dr. Bhim Rao Ambedkar was appointed as the chairman of the Drafting committee.

Question 6:

When was the constitution adopted and passed? When did it come into force?

Answer

Adopted and passed: 26 November 1949.
Come into force: 26 January 1950.

Question 7:

State the significance of January 26.

Answer :

Question 8:

What is the preamble?

Answer :

The Preamble is the introductory part of the constitution, which sets out the main objectives of the constitution.

Question 9;

Explain the significance of the term sovereign.

Answer:

It means that India is its own supreme power and not a subject of any other state or country.

Question 10.

Mention any two features indicating the significance of the preamble.

Answer:

1.The preamble represents the essence, the philosophy, the ideals of the entire constitution of india.

2. It contains the five basic features of the constitution ie. sovereign, socialist, secular, democratic and republic.

Question 11.

Who represented the anglo indians in the constituent assembly /

Answer

Mr. frank anthony and S.H prater

Question 12.

Why is our constitution known as the fundamental law of the land?

Answer

Being superior to the ordinary law of the state, the constitution of India is known as the fundamental law of land.

Structured questions

Question 1

With the reference to the making of indian constitution explain the following

Part a.

When and how……...elected?

Answer 1.

The first sitting of the assembly was held on december 9, 1946

assemblies.

Part b.
How was the membership……..partition of the country?
Answer

Part. c how can you say that constituent …………….of the indian society.

Answer:

The wide ranging membership of the constituent assembly gave representation to all shades of public opinion.it was composed of members from all the categories and communities belonging to india.

Question 2

With the reference to objective resolution

Part a.

Same as the 4th answer.

Part b

Main points

Answer1.

India will be a republic.
The ideals of social, political and economic democracy would be guaranteed to all the people.
The republic would grant fundamental rights to citizens.
The state would safeguard the rights of backward and minorities.

Part c.

Three principles

Answer:

Making indian constitution workable, flexible and strong enough to hold the country together both in peace and in war.
Providing special safeguard to the minorities.
Incorporating the right to constitutional remedies.

Class 9

Chapter 4 (a) Physics

1. Define the term thrust state its S.I.unit.
Ans:- Thrust is the force acting normally on a surface.S.I.unit of thrust is newton (N).
2. What is meant by pressure? state its S.I.unit.
Ans:- Pressure is the thrust per unit area of surface.S.I.unit of pressure is pascal or Nm-2.
3. Define one pascal (Pa), the S.I.unit of pressure.
Ans:- One pascal is the pressure exerted on a surface of area 1m2 by a force of 1N acting normally on it.
4. Differentiate between thrust and pressure.
Ans:-
Thrust
1. Thrust is the force acting normally on surface.
2. Thrust is a vector quantity.
3. S.I.unit of thrust is newton (N).
Pressure
1. Pressure is the thrust per unit area of surface.
2. Pressure is a scalar quantity.
3. S.I.unit of pressure is pascal .
5. How does the pressure exerted by a thrust depend on the area of surface on which it acts.Explain with a suitable example.
Ans:- Pressure is inversly proportional to area.Example:- The ends of nails or pins are made pointed so that large pressure is
exerted through the pointed ends and they can be driven into with a less effort.
6. Why is the tip of an allpin made sharp?
Ans:- The tip of an allpin made sharp so that even a small thrust may cause a great pressure.
7. Explain the following
(a) It is easier to cut with a sharp knife than with a blunt one.
Ans:- It is easier to cut with a sharp knife so that a small thrust may cause a great pressure at the edges and cutting can be
done with the less efforts.
(b) Sleepers are laid below the rails.
Ans:- Wide wooden sleepers are placed below the railway tracks so that the pressure exerted by the iron rails on the ground
become less.
8. What is the fluid?
Ans:- A substance which can flow is called fluid.Example:- Liquids and gases.
9. What do you mean by fluid pressure?
Ans:- Pressure exerted by fluid is called fluid pressure.
10. State three factors on which pressure at a point in a liquid depends.
Ans:-(i) Depth of the point below the free surface (h)
(ii) Density of liquid(p)
(iii) Acceleration due to gravity (g)
11. Write an expression for the pressure at a point inside a liquid .Explain the meaning of the symbols used .
Ans:-P=hpg
Where h is depth
P(rho) is density of liquid
g is acceleration due to gravity.
12. How does the pressure at a certain depth in sea water differ from that at the same depth in river water? Explain your answer.
Ans:-The pressure at a certain depth in sea water is more than that at the same depth in river water. The reason is that the density of sea
water is more than density of river water.
13. Explain why a gas bubble released at the bottom of a lake grows in size as it rises to the surface of lake.
Ans:-The reason is that when the bubble is at the bottom of lake,total pressure exerted on it is the sum of atmospheric pressure and
pressure due to water column.As the gas bubble rises due to decrease in depth the pressure due to water column dereases,so the
total pressure exerted on the bubble decreases.According to Boyle's law, volume of bubble increases due to decreases
in pressure,i.e.the bubble grows in size.
14. A dam has broader walls at the bottom than at the top .Explain.
Ans:-The reason is that the pressure exerted by a liquid increases with its depth.To with stand a greater pressure a dam has broader walls
at the bottom.
15. Why do sea divers need special protective suit?
Ans:-Because in deep sea, the total pressure exerted on the diver's body is much more than his blood pressure.To with stand great
pressure,he or she needs to wear a special protective suit.
16. State the laws of liquid pressure.
Ans:-Following are the five laws of liquid pressure.
(1) Inside the liquid,Pressure increases with increase in depth.
(2) In a stationary liquid,pressure is same at all points on a horizontal plane.
(3) A liquid seeks its own level.
(4) Pressure at same depth is different in different liquid.
(5) Pressure is same in all directions about a point inside the liquid.
17. State Pascal's law of transmission of pressure.
Ans:-Pascal's law states that the pressure exerted anywhere in a confined liquid is transmitted equally and undiminishhed
in all directions throughout the liquid.
18. Name two applications of Pascal's law.
Ans:-(1) Hydraullic jack
(ii) Hydraullic brakes.
19. Explain the principle of a hydraullic macchine.Name two devices which work on this principle.
Ans:-The principle is that a small force applied on a smaller piston is transmitted to produce a large force on the bigger piston.
Devices: (1) Hydraullic press.
(ii) Hydraullic jack.
20. Write one use of hydraullic press.
Ans:-(1) For pessing cotton bales and goods like quilts and books.

Please learn and write on your copy.

Class 9

Chapter 4 Physics

1. What do you mean by atmospheric pressure?
Ans:- The thrust exerted per unit area on the earth surface due to column of air is called atmospheric pressure on the
surface of earth .
2. Name the physical quantity which is expressed in the unit "atm" state its value in pascal ?
Ans:- Atmospheric pressure,1 atm = 1.013X10"5 Pa.
3. We donot feel uneasy even under the enormous pressure of atmosphere above as well as around us give reason.
Ans:- Because pressure of our blood balances it .The bood pressure is slightly more than the atmospheric pressure .
4. State two uses of barometer.
Ans:- 1.To measure atmospheric pressure .
2.For weather forecasting
5. Why does the liquid rise in a syringe when its piston is pulled up?
Ans:- when its piston is pulled up the pressure inside the barrel below the plunger is much less than the
atmospheric pressure acting on the liquid surface.As a result the atmospheric pressure forces the liquid to rise up
in the syringe .
6. What is a barometer ? How is a simple barometer constructed ?
Ans:- An instrument used to measure the atmospheric pressure is called a barometer .
A simple barometer consists of a glass tube of about 1m length closed at one end.Fill the tube with pure mercury and
invert into a trough of mercury in such a way that open end of tube is well immersed in mercury in the trough and
tube stand vertical. Now the thumb is removed .

it is seen that the mercury level in tube falls till its height above
the mercury level in trough becomes h=76cm.
7. Give two reasons for the use of mercury as a barometric liquid.'
Ans:- 1.The mercury neither wets nor sticks to the glass tube,therefore it gives accurate reading.
2.It can easily be obtained in a pure state.
8. Give two reasons why water is not a suitable barometric liquid ?
Ans:- 1.The vapour pressure of water is high,so its vapours in the vacuum space will make the reading in accurate .
2.Water sticks with the glass tube and wets it.So the reading become inaccurate.
9. Mention two demerits of a simple barometer ?
Ans:- 1.There is no protection for the glass tube.
2.It is inconvenient to move the barometer from one place to another i.e.It is not portable.
10. State two advantages of an aneroid barometer over a simple barometer?
Ans:- 1.This barometer has no liquid .
2.It is light and portable therefore it can easily be carried from one place to another.
11. State two factors which affects the atmospheric pressure as we go up?
Ans:- 1.Height of air column .
2.Density of air.
12. Why does a fountain pen leak at a high altitude ?
Ans:- When the pen is taken at an altitude,the atmospheric pressure at this altitude is low.So the excess pressure due to
air inside the rubber tube forces the ink to leak out.
13. Why does nose start bleeding on high mountains?
Ans:- At high altitude since the the atmospheric is low,breathing becomes difficult and nose bleeding may occur due to
excess of blood pressure over the atmospheric pressure .
14. What do the following indicate in barometer regarding weather?
(a) gradual fall in mercury level.
Ans:- Possibility of rain.
(b) Sudden fall in mercury level.
Ans:- Coming of storm or cyclone.
(c) gradual rise in the mercury level.
Ans:- dry weather.

lass 9

Chapter 1 - The Language of Chemistry Exercise Ex. 1(C)

Question 1

Calculate the molecular mass of the following:

CuSO₄·5H₂O

Given atomic mass of Cu = 63·5, H = 1, O = 16, C=12, N = 14, Mg = 24, S = 32

Solution 1

Molecular mass of CuSO₄.5H₂O

63.5 + 32 + (4 × 16) + (10 × 1) + (5 × 16)

= 63.5 + 32 + 64 + 10 + 80

= 249.5

Question 2

Fill in the blanks:

a. Dalton used symbol _____ for oxygen _____ for hydrogen.

b. Symbol represents _____ atom(s) of an element.

c. Symbolic expression for a molecule is called _____. .

d. Sodium chloride has two radicals. Sodium is a _____ radical while chloride is _____ radical.

e. Valency of carbon in CH₄ is _____ , in C₂H₆_____, in C₂H₄ ___ and in C₂H₂ is ____.

f. Valency of Iron in FeCl₂ is _____ and in FeCl₃ it is ____ .

g. Formula of iron (ill) carbonate is _____ .

Solution 2

a. Dalton used symbol [O] for oxygen,[H] for hydrogen.

b. Symbol represents gram atom(s) of an element.

c. Symbolic expression for a molecule is called molecular formula.

d. Sodium chloride has two radicals. Sodium is a basic radical, while chloride is an acid radical.

e. Valency of carbon in CH₄ is 4, in C₂H₆4, in C₂H₄4 and in C₂H₂ is 4.

f. Valency of iron in FeCl₂ is 2 and in FeCl₃ it is 3.

g. Formula of iron (III) carbonate is Fe₂[CO₃]₃.

Question 3

Complete the following table.

Solution 3

Question 4

Sodium chloride reacts with silver nitrate to produce silver chloride and sodium nitrate

a. Write the equation.

b. Check whether it is balanced, if not balance it.

c. Find the weights of reactants and products.

d. State the law which this equation satisfies.

Solution 4

a. NaCl + AgNO₃ → NaNO₃ + AgCl↓

b. It is a balanced equation.

c. Weights of reactants: NaCl - 58.44, AgNO₃ - 169.87

Weights of products: NaNO₃ - 84.99, AgCl - 143.32

NaCl + AgNO₃ → NaNO₃ + AgCl

(23+35.5) + (108+14+48) → (23+14+48) + (108+35.5)

58.5 + 170 → 85 + 143.5

228.5 g → 228.5 g

d. Law of conservation of mass: Matter is neither created nor destroyed in the course of a chemical reaction.

Question 5

What information does the following chemical equation convey?

Zn + H₂SO₄ → ZnSO₄+ H₂

Solution 5

This equation conveys the following information:

i. The actual result of a chemical change.

ii. Substances take part in a reaction, and substances are formed as a result of the reaction.

iii. Here, one molecule of zinc and one molecule of sulphuric acid react to give one molecule of zinc sulphate and one molecule of hydrogen.

iv. Composition of respective molecules, i.e. one molecule of sulphuric acid contains two atoms of hydrogen, one atom of sulphur and four atoms of oxygen.

v. Relative molecular masses of different substances, i.e. molecular mass of

Zn = 65

H₂SO₄ = (2+32+64) = 98

ZnSO₄= (65+32+64) = 161

H₂ = 2

vi. 22.4 litres of hydrogen are formed at STP.

Question 6

What information do the following chemical equations convey? Mg + 2HCl → MgCl₂+ H₂

Solution 6

This equation conveys the following information:

i. Magnesium reacts with hydrochloric acid to form magnesium chloride and hydrogen gas.

ii. 24 g of magnesium reacts with 2(1 + 35.5) = 73 g of hydrochloric acid to produce (24 + 71), i.e. 95 g of magnesium chloride.

iii. Hydrogen produced at STP is 22.4 litres.

Question 7

What are polyatomic ions? Give two examples.

Solution 7

A polyatomic ion is a charged ion composed of two or more covalently bounded atoms. Examples: Carbonate (CO₃^2-) and sulphate (SO₄^2-)

Question 8

Name the fundamental law that is involved in every equation.

Solution 8

Fundamental laws which are involved in every equation:

i. A chemical equation consists of formulae of reactants connected by a plus sign (+) and arrow (→) followed by the formulae of products connected by the plus sign (+).

ii. The sign of an arrow (→) is to read 'to form'. It also shows the direction in which the reaction is predominant.

The fundamental law followed by every equation is 'Law of Conservation of Mass'.

Question 9

What is the valency of :

fluorine in CaF₂

Solution 9

Valency of fluorine in CaF₂is -1.

Question 10

What is the valency of :

sulphur in SF₆

Solution 10

Valency of sulphur in SF₆ is -6.

Question 11

What is the valency of :

phosphorus in PH₃

Solution 11

Valency of phosphorus in PH₃ is +3.

Question 12

What is the valency of :

carbon in CH₄

Solution 12

Valency of carbon in CH₄ is +4.

Question 13

What is the valency of :

nitrogen in the following compounds:

(i) N₂O₃ (ii) N₂O₅ (iii) NO₂ (iv) NO

(ii) Mno2 (2)Cu20 ( 3)Mg3N2

Solution 13

Valency of nitrogen in the given compounds: (2)(1) Mn=4 (2) cu=1 (3)mg=2

i. N₂O₃ = N is +3

ii. N₂O₅ = N is +5

iii. NO₂ = N is +4

iv. NO = N is +2

Question 14

Why should an equation be balanced? Explain with the help of a simple equation.

Solution 14

According to the law of conservation of mass, 'matter can neither be created nor can it be destroyed'. This is possible only if the total number of atoms on the reactants side is equal to the total number of atoms on the products side. Thus, a chemical reaction should always be balanced.

e.g. KNO₃ → KNO₂ + O₂

In this equation, the number of atoms on both sides is not the same, and the equation is not balanced.

The balanced form of this equation is

2KNO₃ → 2KNO₂ + O₂

Question 15

Write the balanced chemical equations of the following reactions. sodium hydroxide + sulphuric acid → sodium sulphate + water

Solution 15

2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

Question 16

Write the balanced chemical equations of the following reactions. potassium bicarbonate + sulphuric acid → potassium sulphate + carbon dioxide + water

Solution 16

2KHCO₃ + H₂SO₄ → K₂SO₄ + 2CO₂ + 2H₂O

Question 17

Write the balanced chemical equations of the following reactions. iron + sulphuric acid → ferrous sulphate + hydrogen.

Solution 17

Fe + H₂SO₄ → FeSO₄ + H₂

Question 18