Equilibrium

Question 1

The correct order of solubility of the given salts in water at 298 K is AgBr — Ksp at 298 K = 5.0 × 10⁻¹³ Zn(OH)₂ — Ksp at 298 K = 1.0 × 10⁻¹⁵ Hg₂Cl₂ — Ksp at 298 K = 1.3 × 10⁻¹⁸

Accepted Answer

Zn(OH)₂ > AgBr > Hg₂Cl₂. Ksp values cannot be compared directly across salts of different stoichiometry — that is the whole trap. AgBr is AB type, so S = √Ksp ≈ 7.1 × 10⁻⁷. Zn(OH)₂ and Hg₂Cl₂ are AB₂ type with Ksp = 4S³, giving S ≈ 6.3 × 10⁻⁶ and 6.9 × 10⁻⁷. So Zn(OH)₂ is the most soluble despite having a smaller Ksp than AgBr.

Answer

Hg₂Cl₂ > Zn(OH)₂ > AgBr

Answer

AgBr > Zn(OH)₂ > Hg₂Cl₂

Answer

Hg₂Cl₂ > AgBr > Zn(OH)₂

Question 2

For the reaction A(g) ⇌ 2B(g), the backward reaction rate constant is higher than the forward reaction rate constant by a factor of 2500, at 1000 K. [Given: R = 0.0831 L atm mol⁻¹ K⁻¹] K_P for the reaction at 1000 K is

Accepted Answer

0.033. At equilibrium K_C is the ratio of the forward to the backward rate constant, so K_C = k_f/k_b = 1/2500 = 4 × 10⁻⁴. The two constants are related by K_P = K_C(RT)^Δn, where Δn is the change in the number of moles of gas. Here Δn = 2 − 1 = 1, so K_P = (1/2500) × 0.0831 × 1000 = 83.1/2500 = 0.033.

Answer

83.1

Answer

2.077 × 10⁵

Answer

0.021

Question 3

Higher yield of NO in N₂(g) + O₂(g) ⇌ 2NO(g) can be obtained at [ΔH of the reaction = +180.7 kJ mol⁻¹] A. Higher temperature B. Lower temperature C. Higher concentration of N₂ D. Higher concentration of O₂

Accepted Answer

A, C, D only. By Le Chatelier’s principle, the reaction is endothermic since ΔH is positive, so supplying heat drives the equilibrium forward and a higher temperature raises the yield — which rules B out and puts A in. Increasing the concentration of either reactant also shifts the equilibrium to the right, so both C and D help. Note that pressure has no effect here, because the number of gaseous moles is two on each side.

Answer

A, D only

Answer

B, C only

Answer

B, C, D only

Q1.The correct order of solubility of the given salts in water at 298 K is

Q2.For the reaction A(g) ⇌ 2B(g), the backward reaction rate constant is higher than the forward reaction rate constant by a factor of 2500, at 1000 K. [Given: R = 0.0831 L atm mol⁻¹ K⁻¹] K_P for the reaction at 1000 K is

Q3.Higher yield of NO in N₂(g) + O₂(g) ⇌ 2NO(g) can be obtained at [ΔH of the reaction = +180.7 kJ mol⁻¹]