The rate constants, K, can be expressed in many different terms. In this case, Kp is the equilibrium constant expressed in terms of gas partial pressure. The formula for this is:
Kp = [P(product C) × P(product D)] / [P(reactant A) × P(reactant B)]
As there is only one product, we will use only its pressure in the numerator.
Kp = [P(COCl2)] / [P(CO) × P(Cl2)]
P(COCl2) = 1.49 × 10⁸ × 2.22 × 10⁻⁴ × 2.22 × 10⁻⁴
P(COCl2) = 7.34 atm