Pressure Equilibrium Constant

In case of gases their partial pressures can also be used in place of molar concentrations (since the two are directly proportional to each other) in the law of equilibrium. The new equilibrium constant, K_p, is called the pressure equilibrium constant.

For the general gas phase reaction:

a A (g) + b B (g) ⇌ c C (g) + d D (g)

pressure equilibrium constant it is given by