For the reaction of gaseous nitrogen with gaseous hydrogen to produce gaseous ammonia, the correct equilibrium constant expression is _____.

Keq = NH3 squared divided by (N2 times H2).
Keq =
Keq = NH3 divided by (N times H2 cubed).
Keq = NH3 divided by (N2 times H2).

Keq = NH3 divided by (N2 times H2).