Question

At 500K the reaction PCl5(g) ↔ PCl3(g) + Cl2(g) has a Kp = 0.497. In an equilibrium mixture at 500K,

the partial pressure of PCl5 is 0.860 atm and PCl3 is 0.350 atm.

What is the partial pressure of Cl2 in the equilibrium mixture?

Answer 1

Solution:

The balanced chemical equation:

PCl₅(g) ↔ PCl₃(g) + Cl₂(g)

The equilibrium expression for the reaction system:

For P_Cl2:

K_p = 0.497

P_PCl5 = 0.860 atm

P_PCl3 = 0.350 atm

Substitute the known partial pressures and K_p into the expression and solve for P_Cl2:

Answer: The partial pressure of Cl₂ in the equilibrium mixture is 1.22 atm.