MCQ on Class 11 Chemistry Chapter 7 Chemical Equilibrium
Questions
1
Which of the following will produce a buffer solution when mixed in equal volumes?
Answer:0.1 mol dm–3 NH4OH and 0.05 mol dm–3 HCl
2
The acidity of BF3 can be explained based on which of the following concepts?
Answer:Lewis concept
⭐ Make GKSeries Your Preferred Source on Google
Add GKSeries as Preferred Source
3
Ka, 2Ka and 3Ka is the respective ionisation constants for the following reactions.
H2S ⇌ H+ + HS–
HS– ⇌ H+ + S2–
H2S ⇌ 2H+ + S2–
The correct relationship between Ka1 , Ka2 and Ka3 is
Answer:Ka3 = Ka1 × Ka2
4
The ionisation constant of an acid, Ka, is the measure of the strength of an acid. The Ka values of acetic acid, hypochlorous acid and formic acid are 1.74 × 10–5, 3.0 × 10–8 and 1.8 × 10–4 respectively. Which of the following orders of pH of 0.1 mol dm–3 solutions of these acids are correct?
Answer:formic acid > acetic acid > hypochlorous acid
5
The pH of neutral water at 25°C is 7.0. As the temperature increases, ionization of water increases, however, the concentration of H+ ions and OH– ions are equal. What will be the pH of pure water at 60°C?
Answer:Less than 7.0
6
When hydrochloric acid is added to cobalt nitrate solution at room temperature, the following reaction takes place and the reaction mixture becomes blue. On cooling the mixture it becomes pink. Based on this information mark the correct answer.
[Co (H2O)6]3+ (aq) + 4Cl–(aq) ⇌ [CoCl4]2– (aq) + 6H2O (l)
(pink) (blue)Answer:∆H > 0 for the reaction
7
Which of the following statements is incorrect?
Answer:The intensity of red colour increases when oxalic acid is added to a solution containing iron (III) nitrate and potassium thiocyanate.
8
PCl5, PCl3 and Cl2 are at equilibrium at 500K in a closed container and their concentrations are 0.8 × 10–3 mol L–1, 1.2 × 10–3 mol L–1 and 1.2 × 10–3 mol L–1 respectively. The value of Kc for the reaction PCl5 (g) PCl3 (g) + Cl2 (g) will be
Answer:1.8 × 10–3
9
Which of the following is not a general characteristic of equilibria involving physical processes?
Answer:All the physical processes stop at equilibrium.
10
For the reaction H2(g) + I2(g) → 2HI (g), the standard free energy is ∆G > 0.
The equilibrium constant (K ) would be __________.
Answer:K < 1
11
Which of the following will produce a buffer solution when mixed in equal volumes ?
Answer:0.1 mol dm–3 NH4OH and 0.05 mol dm–3 HCl
12
We know that the relationship between Kc and Kp is
Kp = Kc (RT)Δ n
What would be the value of Δn for the reaction
NH4Cl (s) ⇔ NH3 (g) + HCl (g)
Answer:2
13
For the reaction H2(g) + I2(g) ⇔ 2HI (g), the standard free energy is ΔG⊖ > 0. The equilibrium constant (K ) would be __________.
Answer:K < 1
14
Which of the following is not a general characteristic of equilibria involving physical processes?
Answer:All the physical processes stop at equilibrium.
15
PCl5, PCl3 and Cl2 are at equilibrium at 500K in a closed container and their concentrations are 0.8 × 10–3 mol L–1, 1.2 × 10–3 mol L–1 and 1.2 × 10–3 mol L–1 respectively. The value of Kc for the reaction PCl5 (g) ⇔ PCl3 (g) + Cl2 (g) will be
Answer:1.8 × 10–3
16
Which of the following statements is incorrect?
Answer:The intensity of red colour increases when oxalic acid is added to a solution containing iron (III) nitrate and potassium thiocyanate.
17
The pH of neutral water at 25°C is 7.0. As the temperature increases, ionisation of water increases, however, the concentration of H+ ions and OH– ions are equal. What will be the pH of pure water at 60°C?
Answer:Less than 7.0
18
The ionisation constant of an acid, Ka, is the measure of strength of an acid. The Ka values of acetic acid, hypochlorous acid and formic acid are 1.74 × 10–5, 3.0 × 10–8 and 1.8 × 10–4 respectively. Which of the following orders of pH of 0.1 mol dm–3 solutions of these acids is correct?
Answer: formic acid > acetic acid > hypochlorous acid
19
Ka1, Ka2 and Ka3 are the respective ionisation constants for the following reactions
H2S ⇔ H+ + HS–
HS– ⇔ H+ + S2–
H2S ⇔ 2H+ + S2–
The correct relationship between Ka1, Ka2 and Ka3 is
Answer:Ka3 = Ka1 * Ka2
20
Acidity of BF3 can be explained on the basis of which of the following concepts?
Answer:Lewis concept
Chapters
