Question

The gas phase reaction

2A(g) ⇋ A₂(g)

at 400 K has ΔGº = + 25.2 kJ mol^–1.

The equilibrium constant KC for this reaction is ......× 10^–2. (Round off to the Nearest integer)

[Use : R = 8.3 J mol^–1K^–1 , ln 10 = 2.3

log₁₀ 2 = 0.30, 1 atm = 1 bar]

[antilog (–0.3) = 0.501]

Answer 1

Using formula

Δ_rGº = –RTlnK_p 

25200 = –2.3 × 8.3 × 400 log(K_p)

K_p = 10^–3.3 = 10^–3 × 0.501

= 5.01 × 10^–4 Bar^–1

= 5.01 × 10^–9 Pa^-1