Which of the following is the correct expression for the concentration based equilibrium constant for the reaction: A (g) + 2 B (g) ⇌ 3 C (g)

Question

A) K_c = [C]³ / [A] [B]²

B) K_c = [C]³

C) K_c = [A] [B]² / [C]³

D) K_c = [A] [2B] / [3C]

Answer 1

The correct answer is A. The equilibrium constant is defined as the product of the concentrations of the products taken to the power of the coefficient in the balanced equation divided by the product of the reactant concentrations taken to their respective coefficients. In general

nA + mB <====> pC + qD

K_c = [C]^p [D]^q / [A]ⁿ [B]^m and so on if more reactants and products are in the balanced equation.