16 mol of `PCl_(5)(g)` is placed in 4 `dm^(-3)` closed vessel. When the temperature is raised to 500 K, it decompses and at equilibrium, 1.2 mol of `PCl_(5)(g)` remains. What is `K_(c)` value for the decomposition of `PCl_(5)(g)` to `PCl_(3)(g)` and `Cl_(2)(g)` at 500K.

Options

A. 0.013
B. 0.05
C. 0.033
D. 0.067

Answer

C

Explanation

`{:(,PCl_(5)(g),hArr,PCl_(3)(g),+,Cl_(2)(g)),("Inital",1.6 "mol",,0,,0),("At eqm.",1.2 "mol",,0.4"mol",,0.4"mol"),("Molar conc.",(1.2)/(4)"mol"dm^(-3),,(0.4)/(4)"mol"dm^(-3),,(0.4)/(4)"mol"dm^(-3)),(,=0.3 mol dm^(-3),,=0.1mol dm^(-3),,=0.1 moldm^(-3)):}`
`K_(c)=([PCl_(3)][Cl_(2)])/([PCl_(5)])=(0.1xx0.1)/(0.3)=0.033`