**Select the correct K expression for the following reaction:**

**The Correct Answer**: K = [C]

^{2}[D]/[A]

^{3}

According to equilibrium expression is product of product raised to its stoichiometric coefficient devided by same of reactant.

3A + B ===== 2C + D

So, K = [C]^{2}[D]/[A]^{3}[B] now for solids its value is 1. so, the last option K = [C]^{2}[D]/[A]^{3} is the correct answer.