Answer: The equilibrium constant expression for the given equation is written below.
Step-by-step explanation:
Equilibrium constant in terms of partial pressure is defined as the ratio of partial pressures of products to the partial pressures of reactants each raised to the power their stoichiometric ratios. It is expressed as

For the general chemical equation:

The expression of
follows:

For the given chemical equation:

The expression of
for above equation follows:

Hence, the equilibrium constant expression for the given equation is written above.