In evacuated closed vessel the total pressure is P bar at equilibrium. Write equilibrium constant `K_p` of the following reaction.
Reaction : `NH_4HS_((s)) hArr NH_(3(g)) + H_2S_((g))`

Explanation

`{:("Reaction:", NH_4HS_((s)) hArr , NH_(3(g))+ , H_2S_((g))), ("Initial concentration:",,Zero,Zero),("Partial pressure at equilibrium:",,p_(NH_3),p_(H_2S)):}`
Total pressure at equilibrium = P bar, So,
`therefore p_(NH_3)=P/2 = p_(H_2S)`
So, `K_p=(p_(NH_3))(p_(H_2S))`
`therefore K_p=(P/2)(P/2)=P^2/4`
`therefore P^2=4K_p` and `P=2sqrt(K_p)`