Class 10 Chemistry

Chemical Reactions and Equations

NCERT Exemplar problems - MCQs part 2

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?

  • Displacement reaction
  • Precipitation reaction
  • Combination reaction
  • Double displacement reaction
  • (i) only
  • (ii) only
  • (iv) only
  • (ii) and (iv)

Answer: (d) (ii) and (iv)

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is

  • 1 : 1
  • 2 : 1
  • 4 : 1
  • 1 : 2

Answer: (b) 2:1

Which of the following is (are) an endothermic process(es)?

  • Dilution of sulphuric acid
  • Sublimation of dry ice
  • Condensation of water vapours
  • Evaporation of water
  • (i) and (iii)
  • (ii) only
  • (iii) only
  • (ii) and (iv)

Answer: (d) (ii) and (iv)

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?

  • Lead sulphate (insoluble)
  • Lead acetate
  • Ammonium nitrate
  • Potassium sulphate

Answer: (b) Lead acetate

Which of the following gases can be used for storage of fresh sample of an oil for a long time?

  • Carbon dioxide or oxygen
  • Nitrogen or oxygen
  • Carbon dioxide or helium
  • Helium or nitrogen

Answer: (d) Helium or nitrogen

The following reaction is used for the preparation of oxygen gas in the laboratory

2KClO3 (s) + heat + catalyst ⇨ 2KCl + 3O2

Which of the following statement(s) is (are) correct about the reaction?

  • It is a decomposition reaction and endothermic in nature
  • It is a combination reaction
  • It is a decomposition reaction and accompanied by release of heat
  • It is a photochemical decomposition reaction and exothermic in nature

Answer: (a) It is a decomposition reaction and endothermic in nature

In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?

  • 2H2 (l) + O2 (l) ⇨ 2H2O (g)
  • 2H2 (g) + O2 (l) ⇨ 2H2O (g)
  • 2H2 (g) + O2 (g) ⇨ 2H2O (l)
  • 2H2 (g) + O2 (g) ⇨ 2H2O (g)

Answer: (c) 2H2 (g) + O2 (g) ⇨ 2H2O (l)

Which of the following are combination reactions?

  • 2KClO3 ⇨ 2KCl + 3O2
  • MgO + H2O ⇨ Mg(OH)2
  • 4Al + 3O2 ⇨ 2Al2O3
  • Zn + FeSO4 ⇨ ZnSO4 + Fe
  • (i) and (iii)
  • (iii) and (iv)
  • (ii) and (iv)
  • (ii) and (iii)

Answer: (d) (ii) and (iii)

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