Explain Gibb's Helmholtz equation.

Gibbs-Helmholtz equation is

                       
The value of ∆G can be zero, positive or negative.

(i) If ∆G = 0, the reaction is in the state of equilibrium i.e. ∆H = T∆S.

(ii) If ∆G = – ve, the reaction is spontaneous in the forward direction.

(iii) If ∆G = +ve, the reaction is non-spontaneous i.e. reaction is spontaneous in the reverse direction.