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Thermodynamics

Question
CBSEENCH11006258

Explain Gibb's Helmholtz equation.

Solution

Gibbs-Helmholtz equation is
                       increment straight G space equals space increment straight H space minus space straight T increment straight S
     where space increment straight G space equals free space energy space change
space space space space space space space space space increment straight H space equals space change space in space enthalpy space and
space space space space space space space space space straight T increment straight S space equals space change space in space randomness space at space temperature space straight T.
Significance of increment straight G.
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.