The Kc units for the reaction N2 (g) + 3H2 (g) -> 2NH3 (g) are:

Explanation

The Kc units for the reaction N2 (g) + 3H2 (g) -> 2NH3 (g) are derived from the equilibrium constant expression for the reaction. The equilibrium constant expression for a reaction is given by: Kc = [NH3]^2 / [N2] * [H2]^3 In this case, the reaction involves gases, so the concentrations of the gases are used in the equilibrium constant expression. The square brackets denote the molar concentrations of the respective species. Therefore, the Kc units for this reaction would be (mol/L)^2 / (mol/L) * (mol/L)^3, which simplifies to mol^-2. So, the units for the equilibrium constant Kc for this reaction are mol^-2. This is consistent with option C.