Relation Between Kp And Kc

K_p And K_c

K_p And K_c are the equilibrium constant of an ideal gaseous mixture. K_p is equilibrium constant used when equilibrium concentrations are expressed in atmospheric pressure and K_c is equilibrium constant used when equilibrium concentrations are expressed in molarity.

For many general chemical reactions aA + bB ⇋ cC + dD

Where a mole of reactant A

b mole of reactant B

c mole of product C

d mole of product D

Consider an example

2A_(g)+B_(g) ⇋ 2C_(g) All in the gas phase.

Ideal Gas Equation

Each of these ideal gas molecules behaves similarly. So for each of them,

PV = nRT

When the change in the number of moles of gas molecules is zero, that is Δn = 0

⇒ K_p=K_c

In general, for any chemical reactions of gas molecules the relation between K_p And K_c is-