Most Important MCQ Questions for Class 10 Science Chapter 1 Chemical Reactions and Equations with Answers

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Q1. 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)

(c) (i) and (iii)


Q2. 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).

(d) Both (b) and (c).


Q3. 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

(c) AC + BD → AD + BC


Q4. 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)

(b) (ii) only


Q5. The following reaction is used for the preparation of oxygen gas in the laboratory:
MCQ Questions for Class 10 Science Chapter 1 Chemical Reactions and Equations with Answers
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.

(a) It is a decomposition reaction and endothermic in nature.


Q6. 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.

(d) Reactants are in gaseous state.


Q7. 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

(b) 2 : 1


Q8. PbS reacts with ozone (O3) and forms pbso4 . As per the balanced equation, molecules of ozone required for every one molecule of PbS is/are

(a) 4
(b) 3
(c) 2
(d) 1

(a) 4


Q9. Copper displaces which of the following metals from its salt solution:

(a) ZnSO4
(b) FeSO4
(c) AgNO3
(d) NiSO4

(c) AgNO3


Q10. What is observed when a solution of potassium iodide is added to silver nitrate solution?

(a) No reaction takes place
(b) White precipitate of silver iodide is formed
(c) yellow precipitate of Agl is formed
(d) Agl is soluble in water.

(b) White precipitate of silver iodide is formed


Q11. Which of the following reactions is not correct:

(a) Zn+ CuSO4 → ZnSO4 + Cu
(b) 2Ag + Cu(NO3)2 → 2AgNO3 + Cu
(c) Fe+CuSO4 → FeSO4 +Cu
(d) Mg + 2HCl → MgCl2 +H2

(b) 2Ag + Cu(NO3)2 → 2AgNO3 + Cu


Q12. When green coloured ferrous sulphate crystals are heated, the colour of the crystal changes because:

(a) it is decomposed to ferric oxide
(b) it loses water of crystallisation
(c) it forms SO2
(d) it forms SO3

(b) it loses water of crystallisation


Q13. In an electrolytic cell where electrolysis is carried, anode has:

(a) Positive change
(b) Negative charge
(c) Connected to negative terminal of the battery
(d) None of these is correct

(a) Positive change


Q14. Pb + CuCl2 → PbCl2 + Cu
This reaction is an example of:

(a) combination
(b) displacement
(c) decomposition
(d) double displacement

(b) displacement


Q15. A substance which oxidizes itself and reduces other is known as

(a) Oxidising agent
(b) reducing agent
(c) Both (a) and (b)
(d) None of these

(b) reducing agent


Q16. 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

(d) Helium or Nitrogent


Q17. 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

(a) 1:2


Q18. The process of reduction involves

(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

(a) addition of oxygen


Q19. Oxidation is a process which involves

(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

(a) addition of oxygen


Q20. A substance ‘X’ is used in white-washing and is obtained by heating limestone in the absence of air. Identify ‘X’.

(a) CaOCl2
(b) Ca (OH)2
(c) CaO
(d) CaCO3

(b) Ca (OH)2


Q21. 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

(b) Sublimation of dry ice


Q22. Select the oxidising agent for the following reaction:
H2S + I2 > 2HI + S

(a) I2
(b) H2S
(C) HI
(d) S

(a) I2

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