Chemical Reactions and Equations
Class 10th Science Chapter MCQs
Chemical Reactions and Equations Class 10 MCQs Questions
1.
Which of the following are exothermic processes?
(i)
Reaction of water with quick lime
(ii) Dilution of an acid
(iii)
Evaporation of water
(iv) Sublimation of camphor (crystals)
(a) (i) and
(ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (iii) and
(iv)
Answer
Answer: (a) (i) and (ii)
2.
A teacher gave two test tubes to the students, one containing
water and the other containing sodium hydroxide. She asked them to identify the
test tube containing sodium hydroxide solution. Which one of the following can
be used for the identification?
(a) Blue litmus
(b) Red litmus
(c)
Sodium carbonate solution
(d) Dilute hydrochloric
acid
Answer
Answer: (b) Red litmus
3.
Which of the following is not physical change?
(a) Boiling
of water to give water vapour
(b) Melting of ice to give water
(c)
Dissolution of salt in water
(d) Combustion of Liquefied Petroleum Gas
(LPG)
Answer
Answer: (d) Combustion of Liquefied Petroleum Gas (LPG)
4.
The following reaction is an example of a
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
(i)
displacement reaction
(ii) combination reaction
(iii) redox reaction
(iv) neutralisation reaction
(a) (i) and (iv)
(b) (ii) and (iii)
(c)
(i) and (iii)
(d) (iii) and (iv)
Answer
Answer: (c) (i) and (iii)
5.
Which of the following is true for an unbalanced chemical
equation?
(a) Number of atoms is equal on both sides of the equation
(b)
Number of atoms is less on the left side of the equation
(c) Number of atoms
is more on the right side of the equation
(d) Both (b) and
(c).
Answer
Answer: (d) Both (b) and (c).
6. Magnesium ribbon is rubbed before burning because it has a coating of
(a) basic magnesium carbonate
(b) basic magnesium oxide
(c) basic
magnesium sulphide
(d) basic magnesium
chloride
Answer
Answer: a
7. Which of the following statements about the given reaction are
correct?
3Fe (s) + 4H2O (g) → Fe3O4 (s) + 4
H2 (g)
(i) Iron metal is getting oxidised
(ii) Water is getting
reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as
oxidising agent
(a) (i), (zi) and (iii)
(b) (in) and (iv)
(c) (i), (ii)
and (iv)
(d) (ii) and (iv)
Answer
Answer: c
8. Which of the following are exothermic processes?
(i) Reaction of water
with quick lime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals)
(a) (i) and (ii)
(b) (ii) and
(iii)
(c) (i) and (iv)
(d) (ii) and
(iv)
Answer/ Explanation
Answer: a
Explaination: Reason: In both the cases, heat energy is
evolved.
9. Oxidation is a process which involves
(a) addition of oxygen
(b)
addition of hydrogen
(c) removal of oxygen
(d) removal of
hydrogen
Answer
Answer: a
10. The process of reduction involves
(a) addition of oxygen
(b)
addition of hydrogen
(c) removal of oxygen
(d) removal of
hydrogen
Answer
Answer: b
11. Three beakers labelled as A, B and C each containing 25 ml of water were
taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to
the beakers A, B and C respectively. It was observed that there was an increase
in the temperature of the solution contained in beakers A and B, whereas in case
of beaker C, the temperature of the solution falls. Which one of the following
statement(s) is (are) correct?
(i) In beakers A and B, exothermic process has
occurred.
(ii) In beakers A and B, endothermic process has occuBftd.
(iii)
In beaker C exothermic process has occurred.
(iv) In beaker C endothermic
process has occurred.
(a) (i) only
(b) (ii) only
(c) (i) and (iv)
(d) (iv), (ii) and (iii)
Answer
Answer: c
12. Give the ratio in which hydrogen and oxygen are present in water by
volume.
(a) 1:2
(b) 1:1
(c) 2:1
(d)
1:8
Answer
Answer: a
13. Which among the following statement(s) is (are) true?
Exposure of
silver chloride 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
(a) (i) only
(b) (i) and (iii)
(c)
(ii) and (iii)
(d) (iv) only
Answer
Answer: a
14. MnO2 + 4HCl → 2 + 2H2O +
Cl2
Identify the substance oxidized in the above . equation.
(a) MnCl2
(b) HCl
(c) H2O
(d)
MnO2
Answer/ Explanation
Answer: d
Explaination: Reason: In this reaction HCl is oxidised to
Cl2, whereas MnO2 is reduced to
MnCl2.
15. When Ag is exposed to air it gets a black coating of
(a)
AgNO3
(b) Ag2S
(c) Ag2O
(d)
Ag2CO3
Answer
Answer: b
16. Which of the following is an endothermic process?
(a) Dilution of
sulphuric acid
(b) Sublimation of dry ice
(c) Condensation of water
vapours
(d) Respiration in human beings
Answer
Answer: b
17. In the double displacement reaction between aqueous potassium iodide and
aqueous lead nitrate, a yellow precipitate of lead iodide is formed. While
performing the activity if lead nitrate is not available, which of the following
can be used in place of lead nitrate?
(a) Lead sulphate (insoluble)
(&) Lead acetate
(c) Ammonium nitrate
(d) Potassium
sulphate
Answer
Answer: b
18. Select the oxidising agent for the following reaction:
H2S
+ I2 > 2HI + S
(a) I2
(b) H2S
(C)
HI
(d) S
Answer
Answer: a
19. A substance added to food containing fats and oils is called:
(a)
Oxidant
(b) Rancid
(c) Coolant
(d)
Antioxidant
Answer
Answer: d
20. The condition produced by aerial oxidation of fats and oils in foods
marked by unpleasant smell and taste is called:
(a) antioxidation
(b)
reduction
(c) rancidity
(d) corrosion
Answer
Answer: c
21. Electrolysis of water is a decomposition reaction. The mole ratio of
hydrogen and oxygen gases liberated during electrolysis of water is:
(a) 1 :
1
(b) 2:1
(c) 4:1
(d) 1:2
Answer
Answer: b
22. When S02 gas is passed through saturated solution of H2S, which of the
following reaction occurs?
(a) SO2 + 2H2S → 2H20 +
3S
(b) SO2 + 2H2S → H20 + 3S
(c)SO2 +
H2S → H2O + S
(d) SO2 + H2O →
SO3 + H2
Answer
Answer: a
23. Name the products formed when iron filings are heated with dilute
hydrochloric acid
(a) Fe (III) chloride and water
(b) Fe (II) chloride and
water
(c) Fe (II) chloride and hydrogen gas
(d) Fe (III) chloride and
hydrogen gas
Answer/ Explanation
Answer: d
Explaination: Reason: 2Fe + 6HCl → 2FeCl3 (Iron (III)
chloride) + 3H2
24. Pb + CuCl2 → PbCl2 + Cu
The above reaction is an
example of:
(a) combination
(b) double displacement
(c)
decomposition
(d) displacement
Answer
Answer: d
25. Which of the following gases can be used for storage (a) Carbon dioxide
or Oxygen
(b) Nitrogen or Oxygen
(c) Carbon dioxide or Helium
(d)
Helium or Nitrogen
Answer
Answer: d
26. A dilute ferrous sulphate solution was gradu¬ally added to the beaker
containing acidified permanganate solution. The light purple colour of the
solution fades and finally disap¬pears. Which of the following is the correct
explanation for the observation?
(a) KMnO4 is an oxidising agent,
it oxidises FeSO4.
(b) FeSO4 acts as an oxidising agent
and oxidises KMNO4.
(c) The colour disappears due to dilution; no
reaction is involved.
(d) KMnO4 is an unstable compound and
de-composes in presence of FeSO4. to a colourless
compound.
Answer
Answer: a
27. In which of the following chemical equations, the abbreviations represent
the correct states of the reactants and products involved at reaction
temperature?
(a) 2H2 (l) + O2 (l) >
2H2O(g)
(b) 2H2 (g) + O2 (l) >
2H2O (l)
(c) 2H2 (g) + O2 (g) >
2H2O (l)
(d) 2H2 (g) +O2 (g) >
2H2O (g)
Answer
Answer: d
28.
Which option denotes a double displacement reaction?
(a) A
+ B + C
(b) A + B → C
(c) AC + BD → AD + BC
(d) AC + B → AB +
C
Answer
Answer: (c) AC + BD → AD + BC
29.
Which among the following is (are) double displacement
reaction(s)?
(t) Pb + CuCl → PbCl2 + Cu
(ii)
Na2SO4 + BaCl2 → BaSO4 + 2NaCl
(iii) C + O2 → CO2
(iv) CH4 + 2O2
→ CO2 + 2H2O
(a) (i) and (iv)
(b) (ii) only
(c)
(i) and (ii)
(d) (iii) and (iv)
Answer
Answer: (b) (ii) only
30.
The following reaction is used for the preparation of oxygen
gas in the laboratory:
Which of the following statement about the reaction is correct?
(a) It is a
decomposition reaction and endothermic in nature.
(b) It is a combination
reaction.
(c) It is a decomposition reaction and accompanied by release of
heat.
(d) It is a photochemical decomposition reaction and exothermic in
nature.
Answer
Answer: (a) It is a decomposition reaction and endothermic in nature.
31.
Which of the following is Not True with respect to the
neutralisation reaction?
(a) Salt is formed.
(b) Reaction occurs between
an acid and a base.
(c) Reactive element displaces less reactive element.
(d) Reactants are in gaseous state.
Answer
Answer: (d) Reactants are in gaseous state.
32.
Electrolysis of water is a decomposition reaction. The mole
ratio of hydrogen and oxygen gases liberated during electrolysis of water is
(a) 1 : 1
(b) 2 : 1
(c) 4 : 1
(d) 1 : 2
Answer
Answer: (b) 2 : 1
33.
Combustion reactions are always
(a) Exothermic
(b)
Endothermic
(c) Sometimes exothermic
(d) Both (a) and
(b).
Answer
Answer: (a) Exothermic
34.
Barium chloride on reacting with ammonium sulphate forms
barium sulphate and ammonium chloride. Which of the following correctly
represents the type of the reaction involved?
(i) Displacement reaction
(ii) Precipitation reaction
(iii) Combination reaction
(iv) Double
displacement reaction
(a) (i) only
(b) (ii) only
(c) (iv) only
(d)
(ii) and (iv)
Answer
Answer: (d) (ii) and (iv)
35.
Which one of the following processes involve chemical
reactions?
(a) Storing of oxygen gas under pressure in a gas cylinder
(b)
Liquefaction of air
(c) Keeping petrol in a China dish in the open
(d)
Heating copper wire in presence of air at high
temperature
Answer
Answer: (d) Heating copper wire in presence of air at high temperature
36.
In the double displacement reaction between aqueous potassium
iodide and aqueous lead nitrate, a yellow precipitate of lead iodide is formed.
While performing the activity if lead nitrate is not available, which of the
following can be used in place of lead nitrate?
(a) Lead sulphate
(insoluble)
(b) Lead acetate
(c) Ammonium nitrate
(d) Potassium
sulphate
Answer
Answer: (b) Lead acetate
37.
In which of the following chemical equations, the
abbreviations represent the correct states of the reactants and products
involved at reaction temperature?
(a) 2H2(l) + O2(l) →
2H2O(g)
(b) 2H2(g) + O2(l) →
2H2O(l)
(c) 2H2(g) + O2(g) →
2H2O(l)
(d) 2H2(g) + O2(g) →
2H2O(g)
Answer
Answer: (d) 2H2(g) + O2(g) → 2H2O(g)