The equilibrium:
`P_(4)(g)+6Cl_(2)(g) hArr 4PCl_(3)(g)`
is attained by mixing equal moles of `P_(4)` and `Cl_(2)` in an evacuated vessel. Then at equilibrium:

Options

A. `[Cl_(2)] gt [PCl_(3)]`
B. `[Cl_(2)] gt [P_(4)]`
C. `[P_(4)] gt [Cl_(2)]`
D. `[PCl_(3)] gt [P_(4)]`

Answer

C

Explanation

`{:(,P_(4)(g),+,6Cl_(2)(g),hArr,4Pcl_(3)(g)),(underset(("moles"))(t=0),a,,a,,0),(t=t_("eq"),a-x,,a-6x,,4x):}`
`[Cl_(2)]=(a-6x)/(V), [PCl_(3)]=(4x)/(V), [P_(4)]=(a-x)/(V)`
Clearly, `[Cl_(2)] lt [P_(4)]`