PCl5, PCl3 and Cl2 are at equilibrium at 500 K in a closed container and their concentrations are 0.8×10-3 mol L-1, 1.2 × 10-3 mol L-1 and 1.2 × 10-3 mol L-1 respectively. The value of Kc for the reactionPCl5g⇌PCl3g+Cl2g will be