Question

Two reactions and their equilibrium constants are given.

A + 2B −⇀ 2C K₁ = 2.81

2C −⇀ D K₂ = 0.194

Calculate the value of the equilibrium constant for the reaction

D −⇀ A + 2B.

K = ?

Answer 1

Adding the two equations gives:

A + 2B = 2C K₁=2.93

+

2C = D K₂=0.258

Result:

A + 2B + 2C = 2C + D

K₁ + K₂

Remove 2С:

A + 2B = D

K₁ + K₂ = 2.93 + 0.258 = 3.188

Reversed reaction:

D = A + 2B

K₃ = 1 / 3.188 = 0.314