Question

Both the forward and reverse reactions in the following equilibrium are believed to be elementary steps:

CO (g) + Cl₂ (g) <----> COCl (g) + Cl (g)

At 25C, the rate constants for the forward and reverse reactions are 2.1x10^-29 M^-1s^-1 and 8.8x10⁹ M^-1s^-1, respectively.

a) What is the value for the equilibrium constant at 25C?

b) Are the reactants or products favored at equilibrium?

Answer 1

(a) Given : rate constant for forward reaction, k_f = 2.1 x 10^-29 M^-1s^-1

rate constant for reverse reaction, k_r = 8.8 x 10⁹ M^-1s^-1

Equilibrium constant, K = (rate constant for forward reaction) / (rate constant for reverse reaction)

K = k_f / k_r

K = (2.1 x 10^-29 M^-1s^-1) / (8.8 x 10⁹ M^-1s^-1)

K = 2.4 x 10^-39

(b) Since value of equilibrium constant is less that 1, therefore reverse reaction is dominating than the forward reaction and reactants are favored at equilibrium.