Question

Consider the reaction in chemical equilibrium. COCl2(g) mc026-1.jpg CO(g) + Cl2(g) Which is the correct equation for K?

Answer 1

K=[CO][Cl^2] / [COCl^2]

Answer 2

Answer: $K_c=\frac{[CO][Cl_2]}{[COCl_2]}$ or $K_p=\frac{[p_{CO}][p_{Cl_2}]}{[p_{COCl_2}]}$

Explanation: Equilibrium constant is the ratio of product of the concentration of products to the product of the concentration of reactants each term raised to their stochiometric coefficient.

For reactions taking place in gaseous phase, equilibrium constant is written in terms of pressure as :

$K_p=\frac{[p_{CO}][p_{Cl_2}]}{[p_{COCl_2}]}$

In term of concentration, equilibrium constant is written as :

$K_c=\frac{[CO][Cl_2]}{[COCl_2]}$