PCl _ 5 dissociates as PCl _ 5 (g) ⇌ PCl _ 3 (g) + Cl _ 2 (g) 5...

{PCl}_{5}$dissociates as${PCl}_{5}\left(g\right) ⇌ {PCl}_{3}\left(g\right) + {Cl}_{2}\left(g\right)$5$ moles of ${PCl}_{5}$ are placed in a $200$ litre vessel which contains $2$ moles of ${N}_{2}$ and is maintained at $600K$. The equilibrium pressure is $2 . 46atm$. The equilibrium constant ${K}_{p}$ for the dissociation of ${PCl}_{5}$ is___$\times {10}^{- 3}$. (nearest integer) (Given: $R = 0 . 082L$ atm ${K}^{- 1}{mol}^{- 1}$; Assume ideal gas behaviour)