Chemical Equilibrium Class 11 MCQs

1 Find the conjugate acid of NH₂^–

A NH₃

B NH₄OH

C NH₄⁺

D NH₂^–

View Answer

Answer:NH₃

2 On increasing the concentration of reactants in a reversible reaction, then equilibrium constant will

A depend on the concentration

B increase

C unchanged

D decrease

View Answer

Answer:unchanged

3 Find the increase in equilibrium concentration of Fe³⁺ ions if OH^– ions concentration decreases to 1/4th in the following reaction

A 8 times

B 16 times

C 4 times

D 64 times

View Answer

Answer:64 times

4 What will be the pH of a buffer solution having an equal concentration of B^– and HB (K_b = 10^-10 for B^–)

A 7

B 4

C 10

D 6

View Answer

Answer:4

5 The equilibrium constant is 278 for the reaction

at the same temperature, what will be the equilibrium constant for the following reaction?

A 6 x 10^-2

B 1.8 x 10^-3

C 1.3 x 10^-5

D 3.6 x 10^-5

View Answer

Answer:6 x 10^-2

6 Highest pH will be recorded for which of the following solutions if they are equimolar

A AlCl₃

B BaCl₂

C BeCl₂

D LiCl

View Answer

Answer:BaCl₂

7 Find the equilibrium constant of the reaction

If the equilibrium constant for the following reactions are given

Eqilibrium

A K₂K₃/K₁

B K₁K₃³/K₂

C K₂K₃³/K₁

D K₂³K₃/K₁

View Answer

Answer:K₂K₃³/K₁

8 In 0.10 M aqueous solution of pyridine (C₅H₅N), find the percentage of pyridine that forms pyridinium ion (C₅H₅N⁺H) (K_b for C₅H₅N = 1.7 x 10^-9 )

A 1.6%

B 0.77%

C 0.0060%

D 0.013%

View Answer

Answer:0.013%

9 Which of the following aqueous solution will be the best conductor of electricity?

A NH₃

B CH₃COOH

C HCl

D C₆H₁₂O₆

View Answer

Answer:HCl

10 Find the pH of a solution when 0.01 M HCl and 0.1 M NaOH are mixed in equal volumes

A 12.65

B 1.04

C 7.0

D 2.0

View Answer

Answer:12.65

11 At a particular temperature and atmospheric pressure, the solid and liquid phases of a pure substance can exist in equilibrium. Which of the following Does the term define this temperature?

A Normal melting point

B Equilibrium temperature

C Boiling point

D Freezing point

View Answer

Answer:A, D

12 For the reaction N2O4 (g) ⇌ 2NO2 (g), the value of K is 50 at 400 K and 1700 at 500 K. Which of the following options is correct?

A The reaction is endothermic

B The reaction is exothermic

C If NO2 (g) and N2O4 (g) are mixed at 400 K at partial pressures 20 bar and 2 bar respectively, more N2O4 (g) will be formed.

D The entropy of the system increases.

View Answer

Answer:A, C, D

13 In which of the following reactions, the equilibrium remains unaffected on addition of small amount of argon at constant volume?

A H2 (g) + I2 (g) ⇌ 2HI (g)

B PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)

C N2 (g) + 3H2 (g) ⇌ 2NH3 (g)

D The equilibrium will remain unaffected in all the three cases.

View Answer

Answer:The equilibrium will remain unaffected in all the three cases.

14 At 500 K, the equilibrium constant, 6Kc, for the following reaction is 5.

1/2 H2 (g) +1/2 I2 (g) ⇌ HI (g)

What would be the equilibrium constant Kc for the reaction 2HI (g) ⇌ H2 (g) + I2 (g)

A 0.04

B 0.4

C 25

D 2.5

View Answer

Answer:0.04

15 What will be the correct order of vapour pressure of water, acetone and ether at 30°C. Given that among these compounds, water has a maximum boiling Do point and ether have a minimum boiling point?

A Water < ether < acetone

B Water < acetone < ether

C Ether < acetone < water

D Acetone < ether < water

View Answer

Answer:Water < acetone < ether

16 On increasing the pressure, in which direction will the gas-phase reaction proceed to re-establish equilibrium, is predicted by applying Le Chatelier’s principle. Consider the reaction.

N2 (g) + 3H2 (g) ⇌ 2NH3 (g)

Which of the following is correct, if the total pressure at which the equilibrium is established, is increased without changing the temperature?

A K will remain the same

B K will decrease

C K will increase

D K will increase initially and decrease when pressure is very high

View Answer