Chapter 18, Problem 26E

Consider the following system at equilibrium at $\text{500}\text{K}$: ${\text{PCl}}_3\left(\text{g}\right)+{\text{Cl}}_2\left(\text{g}\right)\rightleftharpoons {\text{PCl}}_5\left(\text{g}\right)$. When some chlorine is removed from the equilibrium system at constant temperature, in what direction must the reaction run? What will happen to the concentration of ${\text{PCl}}_5$?