The unit of Kc for reaction N2 + O2 ⇌ 2NO?

mol dm^-3

mol^-2 dm^6

mol^-1dm3

No unit

The equilibrium constant, Kc, for the reaction:

N2 + O2 ⇌ 2NO is unitless (No unit).

Since the number of moles of gas is the same on both the reactant and product sides (2 moles).

The concentration terms in the equilibrium constant expression cancel out, leaving Kc without units.