Practice sheets
DPP
Class 10 - Science
Section A
1.
2.
3.
The colour of the ferrous sulphate solution is
[1]
a) Blue
b) Colourless
c) Pale green
d) Reddish-brown
Which of the following metals will change the blue colour of copper sulphate solution?
a) Gold
b) Silver
c) Platinum
d) Zinc
Which of the following is(are) an endothermic process(es)?
[1]
[1]
i. Dilution of sulphuric acid
ii. Sublimation of dry ice
iii. Condensation of water vapours
iv. Evaporation of water
4.
a) (iii) only
b) (ii) and (iv)
c) (i) and (iii)
d) (ii) only
A student added zinc granules to copper sulphate solution taken in a test tube. Out of the following, the correct
[1]
observations made by the student will be
A. Zinc granules have no regular shape.
B. Zinc granules have silvery grey colour.
C. The colour of zinc granules changed to brownish-black.
5.
6.
7.
a) C only
b) B only
c) A only
d) All of these
The name given to the expression of a reaction in terms of formulae of reactants and products is
a) Chemical reaction
b) Redox reaction
c) Chemical equation
d) Chemical composition
On the basis of evolution or absorption of heat, chemical reactions can be divided in how many types ?
a) One
b) Two
c) Three
d) Four
Strong heating of ferrous sulphate leads to the formation of a brown solid and two gases. This reaction can be
[1]
[1]
[1]
categorised as:
a) displacement and redox
b) displacement and endothermic
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c) decomposition and exothermic
8.
d) decomposition and redox
The colour of the solid product formed on heating ferrous sulphate is
a) Reddish-brown
b) Green
c) Black
d) Colourless
[1]
[1]
9.
Obseravation
I
II
III
Solution after reaction
Colourless
Colourless
Colourless
Metal Deposited
Zn
Cu
Fe
Which of the following is correct conclusion?
a) Al is more reactive than Cu and Fe but less
reactive than Zn
c) Al is more reactive than Zn and Cu but less
b) Al is more reactive than Cu but less reactive
than Zn and Fe
d) Al is more reactive than Zn, Cu, Fe
reactive than Fe
10.
For the reaction, 3Fe + 4H2O → Fe2O3 + 4H2. Which of the following statement is correct?
[1]
A. Iron is oxidized
B. Water is reduced
C. Water act as reducing agent
D. Iron act as reducing agent
11.
a) A, B and D
b) B and D
c) A and D
d) All of these
Assertion (A): In a reaction, Zn(s) + CuSO4(aq) ⟶ ZnSO4(aq) + Cu(s)
[1]
Zn is a reductant but itself get oxidized
Reason (R): In a redox reaction, the oxidant is reduced by accepting electrons and reductant is oxidized by
losing electrons.
a) Both A and R are true and R is the correct
explanation of A.
c) A is true but R is false.
12.
b) Both A and R are true but R is not the
correct explanation of A.
d) A is false but R is true.
Assertion (A): Following is a balanced chemical equation for the action of steam on iron:
[1]
3Fe + 4H2O → Fe3O4 + 4H2
Reason (R): The law of conservation of mass holds good for a chemical equation.
a) Both A and R are true and R is the correct
explanation of A.
c) A is true but R is false.
13.
b) Both A and R are true but R is not the
correct explanation of A.
d) A is false but R is true.
Assertion (A): To dilute sulphuric acid, acid is added to water and not water to acid.
[1]
Reason (R): Specific heat of water is quite large.
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a) Both A and R are true and R is the correct
b) Both A and R are true but R is not the
explanation of A.
correct explanation of A.
c) A is true but R is false.
14.
d) A is false but R is true.
Assertion (A): Silver bromide is kept in the coloured bottles.
[1]
Reason (R): Silver bromide is kept in coloured bottles because it decomposes in presence of light.
a) Both A and R are true and R is the correct
b) Both A and R are true but R is not the
explanation of A.
correct explanation of A.
c) A is true but R is false.
15.
d) A is false but R is true.
Assertion (A): In a reaction of copper with oxygen, copper serves as a reducing agent.
[1]
Reason (R): The substance which gains oxygen in a chemical reaction is a reducing agents.
a) Both A and R are true and R is the correct
b) Both A and R are true but R is not the
explanation of A.
correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.
16.
Give one example of endothermic reaction.
[1]
17.
Translate the following statement into a chemical equation and then balance it :
[1]
Hydrogen gas combines with nitrogen to form ammonia.
18.
Complete the missing components/ variables given as x and y in the reaction
[1]
Pb(NO3)2 (aq) + 2KI(aq) ⟶ PbI2 (x) + 2KNO3 (y)
19.
What does the symbol (aq) represent in a chemical equation?
[1]
20.
Identify the substance oxidized and reduced in the following reaction.
[1]
C uO(s) + Zn(s) → ZnO(s) + C u(s)
Section B
21.
What is the difference between rusting and burning?
[2]
22.
Identify the type of chemical reaction taking place in each of the following.
[2]
i. Barium chloride solution is mixed with a copper sulphate solution and a white precipitate is observed.
ii. On heating copper powder in the air in a China dish, the surface of copper powder turns black.
iii. On heating, green coloured ferrous sulphate crystals, reddish brown solid is left and the smell of a gas having
the odour of burning sulphur is experienced.
iv. Iron nails when left dipped in blue copper sulphate solution become brownish in colour and the blue colour
of copper sulphate fades away.
v. Quicklime reacts vigorously with water releasing a large amount of heat.
23.
i. Why is respiration considered as an exothermic reaction?
[2]
ii. Define the terms oxidation and reduction.
iii. Identify the substance that is oxidised and reduced in the following reaction.
24.
Discuss oxidation and reduction according to electronic concept.
[2]
25.
What is the difference between combination and decomposition reactions? Write an equation of each type.
[2]
26.
Balance the following chemical equations and state whether they are exothermic or endothermic.
[2]
i. N a + H
2O
ii. F eSO
4
27.
→ N aOH + H2
→ F e2 O3 + S O2 + S O3
Why is respiration considered as exothermic reaction ? Explain.
[2]
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28.
Identify the oxidising agent (oxidant) in the reaction:
[2]
CuSO4 + Zn ⟶ Cu + ZnSO4
29.
Complete and balance the following equations:
i. Cu + O2
[2]
Heat
⟶
ii. MnO2 + 4HCI ⟶
30.
What is double displacement reaction?
[2]
Section C
31.
What happens when dilute hydrochloric acid is added to iron filings?
[3]
32.
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
[3]
33.
A brown substance X on heating in air forms a substance Y. When hydrogen gas is passed over heated Y, it again [3]
changes back into X. Name the substances X and Y.
34.
i. Why are the chips packets puffed when we buy them from market?
[3]
ii. Paint is applied on articles made up of iron, why?
35.
2g of silver chloride is taken in a china dish and the china dish is placed in sunlight for some time. What will be
[3]
your observation in this case ? Write the chemical reaction involved in the form of a balanced chemical equation.
Identify the type of chemical reaction.
36.
On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a
[3]
brown gas X is formed.
i. Write a balanced chemical equation of the reaction.
ii. Identify the brown gas X evolved.
iii. Identify the type of reaction.
iv. What could be the pH range of the aqueous solution of the gas X?
37.
Give reason and name the type of chemical reaction taking place in each case:
[3]
i. Dissolution of ammonium chloride in water leads to cooling of the glass apparatus used for dissolutions.
ii. Silver chloride powder which is white in colour, turns grey when kept in sunlight.
iii. Blue colour of copper sulphate solution fades when an iron nail is dipped inside the solution.
38.
Translate the following statement into a chemical equation and then balance it :
[3]
Barium chloride reacts with aluminium sulphate to give aluminium.
39.
Why are decomposition reactions called the opposite of combination reactions? Write equations for these
[3]
reactions.
40.
A student burns a metal A found in the form of ribbon.The ribbon burns with a dazzling flame & a white powder [3]
B is formed which is basic in nature. Identify A & B. Write the balanced chemical equation for the reaction
involved.
Section D
Question No. 41 to 44 are based on the given text. Read the text carefully and answer the questions:
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Those reactions in which two compounds react by an exchange of ions to form two new compounds are called double
displacement reactions. A double displacement reaction usually occurs in solution and one of the products, being
insoluble, precipitate out (separates as a solid). Any reaction in which an insoluble solid (called precipitate) is formed
that separates from the solution is called a precipitation reaction. The reaction in which acid or acidic oxide reacts with
base or basic oxide to form salt and water is called neutralisation reaction.
For example, 2NaOH + H2SO4 ⟶ Na2SO4 + H2O
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41. When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide
is obtained and the sulphuric acid so formed remains in the solution. Mention the type of reaction.
42. Balance the following chemical reaction.
Pb(NO3)2(aq) + KI(aq) ⟶ PbI2(s) + KNO3(aq)
43. Barium chloride in reaction with ammonium sulphate forms barium sulphate and ammonium chloride. Which type of
chemical reaction represents in this reaction?
44. Identify A in the following reaction.
AlCl3(aq) + 3NH4OH(aq) ⟶ A + 3NH4Cl(aq)
Section E
Question No. 45 to 49 are based on the given text. Read the text carefully and answer the questions:
5.0
Redox reactions are those reactions in which oxidation and reduction occur simultaneously. A redox reaction is made
up of two half reactions. In the first half reaction, oxidation takes place and in second half reaction, reduction occurs.
Oxidation is a process in which a substance loses electrons and in reduction, a substance gains electrons. The substance
which gains electrons is reduced and acts as an oxidising agent. On the other hand, a substance which loses electrons is
oxidised and acts as a reducing agent.
45. Which of the following is a redox reaction?
a) CaCO3 ⟶ CaO + CO2
b) CaO + 2HCl ⟶ CaCl2 + H2O
c) NaOH + HCl ⟶ NaCl + H2O
d) H2 + Cl2 ⟶ 2HCl
46. Identify the reaction in which H2O2 is acting as a reducing agent
a) H2SO3 + H2O2 ⟶ H2SO4 + H2O
b) 2FeCl2 + 2HC1 + H2O2 ⟶ 2FeCl3 +
2H2O
c) Cl2 + H2O2 ⟶ 2HCl + O2
d) 2HI + H2O2 ⟶ 2H2O + I2
47. For the following reactions, identify the one in which H2S acts as a reducing agent.
a) 2FeCl3 + H2S ⟶ 2FeCl2 + 2HCl + S
b) None of these
c) CuSO4 + H2S ⟶ CuS + H2SO4
d) Cd(NO3)2 + H2S ⟶ CdS + 2HNO
48. For the following reaction, identify the correct statement.
ZnO + CO ⟶ Zn + CO2
a) ZnO is being oxidised
b) ZnO is being reduced
c) CO2 is being oxidised
d) CO is being oxidised
49. In the following reaction, which substance is reduced?
PbS + 4H2O2 ⟶ PbSO4 + 4H2O
a) H2O
b) H2O2
c) PbS
d) PbSO4
Question No. 50 to 54 are based on the given text. Read the text carefully and answer the questions:
5.0
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In decomposition reactions, a single reactant breaks down to form two or more products. Decomposition reaction is
opposite to combination reaction. Thermal decomposition reactions use the energy in form of heat for decomposition of
reactants. Electrolytic decomposition reactions involve the use of electrical energy for the decomposition of reactant
molecules. Photolysis or photochemical decomposition involves the use of light energy for the purpose of
decomposition.
50. Which of the following reactions is a decomposition reaction?
a) NaOH + HCl ⟶ NaCl + H2O
b) H2 + I2 ⟶ 2HI
c) H4CNO ⟶ H2NCONH2
d) 2kClO3 ⟶ 2KCl + 3O2
51. 2Pb(NO3)2 ⟶ 2PbO + nA + O2
What is nA in the given reaction?
a) 4NO2
b) 2PbNO2
c) 4NO
d) NO2
52. Amino acid is formed by the decomposition of which component of our diet?
a) Fat
b) Starch
c) Carbohydrate
d) Protein
53. Silver chloride on exposure to sunlight for a long duration turns grey due to
I. the formation of silver by decomposition of silver chloride
II. sublimation of silver chloride
III. decomposition of chlorine gas from silver chloride
IV. oxidation of silver chloride
The correct statement(s) is/are
a) Only (I) and (II)
b) Only (I)
c) Only (II) and (III)
d) Only (IV)
54. What type of chemical reaction takes place when electricity is passed through water?
55.
a) Electrolytic decomposition
b) Displacement reaction
c) Thermal decomposition
d) Photochemical decomposition
What is meant by displacement reaction and double displacement reaction? Explain with the help of one
[5]
example each.
56.
How is a chemical equation balanced ? Discuss with the help of an example.
[5]
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