Question

A definite mass of solid $N{H}_{4}HS$ is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm pressure. $N{H}_{4}HS$ decomposes to give $N{H}_3$ and $H_{2}S$ and at equilibrium total pressure in flask is 0.84 atm. The equilibrium constant for the reaction is :

• A. 0.3
• B. 0.18
• C. 0.17
• D. 0.11

Answer 1

The correct option is D 0.11

$N{H}_{4}HS\left(s\right)\rightleftharpoons N{H}_3\left(g\right)+H_{2}S\left(g\right)$
Before equilibrium $0.50$
After equilibrium $0.5+PP$

$P_T=0.84=0.5+P+P\therefore P=0.17atm$

$K_p=P_{N{H}_3}^{\prime }\times P_{H_{2}S}^{\prime }$

$=(0.5+0.17)\times 0.17=0.11{atm}^2$

Option (D) is correct.