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)