$\mathrm{PCl}_5$ dissociates as $$ \mathrm{PCl}_5(\mathrm{~g}) \rightleftharpoons \mathrm{PCl}_3(\mathrm{~g})+\mathrm{Cl}_2(\mathrm{~g}) $$ 5 moles of PCl 5 are placed in a 200 litre vessel which contains 2 moles of N 2 and is maintained at 600 K . The equilibrium pressure is 2.46 atm . The equilibrium constant Kp for the dissociation of $\mathrm{PCl}_5$ is $\_\_\_\_$ $\times 10^{-3}$. (nearest integer) (Given: $\mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1} \cdot$ Assume ideal gas behaviour)