The equilibrium constant K for the reaction is:
3H2 (g) + N2 (g) ⇌ 2NH3 (g)
[NH3]2 / { [N2] [H2]3 }
[NH3]2 / { [N2]3 [H2] }
[NH3] / { [N2] [H2] }
The equilibrium constant Kc for the reaction N2 (g) + 3H2 (g)⇋ 2NH3 (g) is: