For which one of the following homogenous equilibrium equations will Kp equal Kc?
3H2 (g) + N2 (g) ⇌ 2NH3 (g)
PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)
COCl2 (g) ⇌ CO (g) + Cl2 (g)
H2 (g) + I2 (g) ⇌ 2HI (g)