CBSE Class 11 Chemistry Chemical Equilibrium MCQs Set 04

Question: 100 mL of 0.01 M solution of NaOH is diluted to 1dm³ . What is the pH of the diluted solution? 
a) 12
b) 11
c) 2
d) 3
Answer: b

Question: The reaction, 2A_(g) + B_(g) ⇌ 3C_(g) + D_(g) is begun with the concentrations of A and B both at an initial value of 1.00 M. When equilibrium is reached, the concentration of D is easured and found to be 0.25 M. The value for the equilibrium constant for this reaction is given by the expression
a) [(0.75)³(0.25)] ÷ [(1.00)²(1.00)]
b) [(0.75)³(0.25)] ÷ [(0.50)²(0.75)]
c) [(0.75)³(0.25)] ÷ [(0.50)²(0.25)]
d) [(0.75)³(0.25)] ÷ [(0.75)²(0.25)]
Answer: b

Question: According to Le Chatelier’s principle, adding heat toa solid and liquid in equilibrium will cause the
a) temperature to increase
b) temperature to decrease
c) amount of liquid to decrease
d) amount of solid to decrease.
Answer: d

Question: What is [H⁺] in mol/L of a solution that is 0.20 M in CH₃COONa and 0.10 M in CH₃COOH? (K_a for CH₃COOH = 1.8 × 10^–5)
a) 3.5 × 10^–4
b) 1.1 × 10^–5
c) 1.8 × 10^–5
d) 9.0 × 10^–6 
Answer: d

Question: Which of the following cannot act both as Bronsted acid and as Bronsted base ?
a) HCO₃ ^–
b) NH₃
c) HCl
d) HSO^– ₄ 
Answer: c

Question: Accumulation of lactic acid (HC₃H5O₃), a monobasic acid in tissues leads to pain and a feeling of fatigue. In a 0.10 M aqueous solution, lactic acid is 3.7% dissociated. The value of issociation constant, Ka, for this acid will be
a) 1.4 × 10^–5
b) 1.4 × 10^–4
c) 3.7 × 10^–4
d) 2.8 × 10^–4
Answer: b

Question: Which one of the following molecular hydrides acts as a Lewis acid?
a) NH₃
b) H₂O
c) B₂H₆
d) CH₄
Answer: c

Question: In liquid-gas equilibrium, the pressure of vapours above the liquid is constant at
a) constant temperature
b) low temperature
c) high temperature
d) none of the options
Answer: a

Question: pH of an aqueous solution containing 10^-8 mol /L of HCI is 
a) 8
b) 10
c) 6.96
d) 12
Answer: c

Question: Which of the following molecules acts as a Lewis acid?
a) (CH₃₎₂O
b) (CH₃)₃P
c) (CH₃)₃N
d) (CH₃)₃B 
Answer: d

Question: For any reversible reaction, if we increase concentration of the reactants, then effect onequilibrium constant
a) depends on amount of concentration
b) unchange
c) decrease
d) increase. 
Answer: b

Question: At 25°C, the dissociation constant of a base, BOH, is 1.0 × 10^–12. The concentration of hydroxyl ions in 0.01 M aqueous solution of the base would be
a) 1.0 × 10^–5 mol L^–1
b) 1.0 × 10^–6 mol L^–1
c) 2.0 × 10^–6 mol L^–1
d) 1.0 × 10^–7 mol L^–1 
Answer: d

Question: Which of the following salts will give highest pH in water?
a) KCl
b) NaCl
c) Na₂CO₃
d) CuSO₄ 
Answer: c

Question: What is the [OH^–] in the final solution prepared by mixing 20.0 mL of 0.050 M HCl with 30.0 mL of 0.10 M Ba(OH)₂?
a) 0.40 M
b) 0.0050 M
c) 0.12 M
d) 0.10 M
Answer: d

Question: The pH of a 0.1 M solution of NH₄ OH (having Kb = 1.0 x 10^-5 ) is equal to
a) 10
b) 6
c) 11
d) 12
Answer: c

Question: Which of these is least likely to act as a Lewis base?
a) BF3
b) PF3
c) CO
d) F–
Answer: a

Question: Which one of the following conditions will favour maximum formation of the product in the reaction A_2(g) + B_2(g) ⇌ X2_(g), ΔrH = –X kJ ?
a) Low temperature and high pressure
b) Low temperature and low pressure
c) High temperature and high pressure
d) High temperature and low pressure
Answer: a

Question: Hydroxyl ion concentration of 10^-2 M HCl is 
a) 1 x 10¹ mol dm^-3
b) 1 x 10^-12 mol dm^-3
c) 1 x 10^-1 mol dm^-3
d) 1 x 10^-14 mol dm^-3
Answer: b

Question: Calculate the pH of a solution in which hydrogen ion concentration is 0.005 g-equi /L. 
a) 2.3
b) 2 .8
c) 2 .9
d) 2.6
Answer: a

Question: The pH of 0.01 M NaOH_(aq) solution will be
a) 7.01
b) 2
c) 12
d) 9
Answer: c

Question: Ionisation constant of CH₃COOH is 1.7 × 10^–5 and concentration of H⁺ ions is 3.4 × 10^–4. Then find out initial concentration of CH₃COOH molecules.
a) 3.4 × 10^–4
b) 3.4 × 10^–3
c) 6.8 × 10^–4
d) 6.8 × 10^–3
Answer: d

Question: What will be the pH value of0.05M Ba (OH)₂ solution?
a) 12
b) 13 
c) 1
d) 12.96
Answer: b

Question: Conjugate acid of NH
a) NH₄OH
b) NH₄⁺
c) NH₂ ^–
d) NH₃ 
Answer: d

Question: Reaction BaO_2(s) ⇌ BaO_(s) + O_2(g); ΔH = +ve. In equilibrium condition, pressure of O₂ depends on
a) increase mass of BaO₂
b) increase mass of BaO
c) increase temperature on equilibrium
d) increase mass of BaO₂ and BaO both. 
Answer: c

Question: Which one of the following statements is not true?
a) Among halide ions, iodide is the most powerful reducing agent.
b) Fluorine is the only halogen that does not show a variable oxidation state.
c) HOCl is a stronger acid than HOBr.
d) HF is a stronger acid than HCl. 
Answer: d

Question: Which solution has pH equal to 10? 
a) 10^-4 M KOH
b) 10-¹⁰ M KOH
c) 10^-10 M HCI
d) 10^-4 M HCl
Answer: a

Question: Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH value?
a) BaCl₂
b) AlCl₃
c) LiCl
d) BeCl₂
Answer: a

Question: In Haber process, 30 litres of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of aseous mixture under the aforesaid condition in the end?
a) 20 litres ammonia, 20 litres nitrogen, 20 litres hydrogen
b) 10 litres ammonia, 25 litres nitrogen, 15 litres hydrogen
c) 20 litres ammonia, 10 litres nitrogen, 30 litres hydrogen
d) 20 litres ammonia, 25 litres nitrogen, 15 litres hydrogen
Answer: b

Question: Calculate pOH of 0.001 M NH₄OH, when it is 1% dissociated in the solution.
a) 5
b) 2.96
c) 9.04
d) 11.4
Answer: a

Question: Calculate the pOH of a solution at 25°C that contains 1 × 10^–10 M of hydronium ions, i.e. H₃O⁺.
a) 4.000
b) 9.000
c) 1.000
d) 7.000 
Answer: a

Question: Which of the following fluoro-compounds is mostlikely to behave as a Lewis base?
a) BF₃
b) PF₃
c) CF₄
d) SiF₄
Answer: b

Question: The value of DH for the reaction X_2(g) + 4Y_2(g) ⇌ 2XY_4(g) is less than zero.Formation of XY_4(g) will be favoured at
a) high temperature and high pressure
b) low pressure and low temperature
c) high temperature and low pressure
d) high pressure and low temperature.
Answer: d

Question: Which one of the following information can be obtained on the basis of Le Chatelier principle?
a) Dissociation constant of a weak acid
b) Entropy change in a reaction
c) Equilibrium constant of a chemical reaction
d) Shift in equilibrium position on changing value of a constraint
Answer: d

Question: Which has highest pH?
a) CH₃COOK
b) Na₂CO₃
c) NH₄Cl
d) NaNO₃
Answer: b

Question: The pH value of 1/1000 N KOH solution is
a) 3
b) 10^-11
c) 2
d) 11
Answer: d