Chlorine gas is added at constant volume and temperature to the equilibrium $\mathrm{PCl}{}_5(\mathrm{g})\rightleftharpoons \mathrm{PCl}{}_3(\mathrm{g})+\mathrm{Cl}{}_2(\mathrm{g})$. At the new equilibrium

1. Athe amount of $\mathrm{PCl}{}_5$ is less than before
2. Bthe amount of $\mathrm{PCl}{}_3$ is greater than before
3. Cthe amount of $\mathrm{PCl}{}_5$ is greater than before
4. D$K_c$ is greater than before