Question

The equilibrium constant, K_c, for the formation of nitrosyl chloride from nitric oxide and chlorine.

2NO(g) + Cl₂(g) ⇌ 2NOCl(g)

is 6.5 ×10⁴ at 35°C. In which direction will the reaction proceed to reach equilibrium if the starting concentrations of NO, Cl₂, and NOCl are 5.2 × 10⁻³M, 3.4 × 10⁻⁴M, and 3.4 M respectively?

Answer 1

SOLUTION

We have the equillibrium reaction

2NO(g) + Cl₂(g) ⇌ 2NOCl(g) K_c =  6.5 ×10⁴ at 35°C

initial concentration    5.2 × 10⁻³M 3.4 × 10⁻⁴M    3.4 M

If the reaction quotient Q > K_c , then the reaction will move in backward direction

If the reaction quotient Q < K_c , then the reaction will move in forward direction

If the reaction quotient Q = K_c , then the reaction is in equillibrium

Calculating Q = [NOCl]² / [Cl₂] [NO]² = [3.4 M]² / [ 3.4 × 10⁻⁴M ] [5.2 × 10⁻³M ]² = 1.26 * 10⁹

So, the reaction quotient Q > K_c , then the reaction will move in backward direction Answer