Phosphorous Trichloride and Phosphorous Pentachloride Equilibrate in the Presence of Molecular

Multiple Choice

Phosphorous trichloride and phosphorous pentachloride equilibrate in the presence of molecular chlorine according to the reaction: PCl₃ (g) + Cl₂ (g) → PCl₅ (g)
An equilibrium mixture at 450 K contains
P_PCl3 = 0.224 atm,
P_Cl2 = 0.284 atm, and
P_PCl5 = 4.24 atm. What is the value of K_p at this temperature?

A) 66.7
B) 1.50 × 10^-2
C) 2.70 × 10^-1
D) 3.74
E) 8.36