Phosphorus pentachloride dissociated as follows in a closed vessel, ${\mathrm{PCl}}_5\left(\mathrm{g}\right)\rightleftharpoons {\mathrm{PCl}}_3\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$ If total pressure at equilibrium of the reaction. Mixture is P and degree of dissociation of PCl₅ is x, the partial pressure of PCl₃ will be