Question

The equilibrium constant for, 2H2S (g) 2H2(g) +

S2(g) is 0.0118 at 1300 K while the heat of dissociation is 597.4 kJ. The standard equilibrium constant of the reaction at 1200 K is :

• A. 1.180 × 10–4
• B. 11.80
• C. 118.0
• D. Cannot be calculated from given data

Answer 1

Answer: (A)

1.180 × 10–4

Answer 2

$\log\frac{K_{2}}{K_{1}} = \frac{\Delta H^{0}}{2.303R}\left\lbrack \frac{1}{T_{1}} - \frac{1}{T_{2}} \right\rbrack$

$\log\frac{K_{2}}{0.0118} = \frac{597.4 \times 10^{3}}{2.303 \times 8.314}\left\lbrack \frac{1}{1300} - \frac{1}{1200} \right\rbrack$

log K2 = – 2 + log (0.0118) = – 3.928

$\Rightarrow$ K2 = 1.18 × 10-4

Therefore, (1) option is correct.