`2 "mole"` of `PCl_(5)` were heated in a closed vessel of `2 litre` capacity. At equilibrium `40%` of `PCl_(5)` dissociated into `PCl_(3)` and `Cl_(2)`. The value of the equilibrium constant is:

Options

A. 0.532
B. 0.266
C. 0.133
D. 0.174

Answer

B

Explanation

`{:(,PCl_(5)(g),hArr,PCl_(3),+,Cl_(2)(g)),("Initial conc.",2//2,,-,,-),("Eqm. conc.",1(1-0.4)M,,1xx0.4M,,1xx0.4M):}`
`K_(C)=([PCl_(3)][Cl_(2)])/([PCl_(5)])`
`=((1xx0.4)(1xx0.4))/((0.6))=0.266`