Question

Consider the heterogeneous equilibrium in a closed container
$NH_{4}HS (s) \rightleftharpoons NH_{3} (g) + H_{2}S(g)$
If more $NH_{4}HS$ is added to the equilibrium

• A. Partial pressure of $NH_{3}$ increases
• B. Partial pressure of $H_{2}S$ increases
• C. Total pressure in the container increases
• D. No effect on partial pressure of $NH_{3}$ and $H_{2}S$

Answer 1

Answer: (D)

$NH_{4}HS (s) \rightleftharpoons NH_{3(g)} + H_{2}S(g)$
$K_{p} = NH_{3}(g ) \times H_{2}S(g)$
Partial pressures of $NH_{3}$ and $H_{2}O$ do not affect $NH_{4}HS(s)$ because $NH_{4}HS(s)$ is solid for solid active mass unity.