Consider the reaction below.

Upper C upper C l subscript 5 (g) double-headed arrow upper P upper C l subscript 3 (g) plus upper C l subscript 2 (g).

At 500 K, the reaction is at equilibrium with the following concentrations.

[PCI5]= 0.0095 M
[PCI3] = 0.020
[CI2] = 0.020 M

What is the equilibrium constant for the given reaction?