Question

For the reaction at 298 K, 

2A + B → C ∆H = 400 kJ mol^–1 and

∆S = 0.2 kJ K^–1 mo^l–1 

At what temperature will the reaction become spontaneous considering ∆H and ∆S to be constant over the temperature range?

Answer 1

From the expression, 

∆G = ∆H – T∆S 

Assuming the reaction at equilibrium, ∆T for the reaction would be: 

                            (∆G = 0 at equilibrium) 

T = 2000 K 

For the reaction to be spontaneous, ∆G must be negative. Hence, for the given reaction to be spontaneous, T should be greater than 2000 K.