The dissociation equilibrium pressure of `NH_(4)HS_((s))` is `60 cm` at `27^(@)C`. The total pressure at equilibrium, when the `NH_(4)HS` is dissociated in pressence of `45 cm` of `NH_(3)` is :

Options

A. `100 cm`
B. `105 cm`
C. `75 cm`
D. `65 cm`

Explanation

`NH_(4)HS_((s))hArrNH_(3)+H_(2)S`
`K_(p)` for `NH_(4)HS=PxxP=P^(2)`
Also given `2P=60 cm :. P=30 cm`
`K_(p)=(30)^(2)=900cm^(2)`
`NH_(4)HS_((s))hArrunderset(p'+45)(NH_(3))+underset(P')(H_(2)S)`
`(P'+45)xxP'=900`
`:. P'=15cm`
`:. P_(T)=15+45+15=75 cm`