Explanation :
As we know that the Gibbs free energy is not only function of temperature and pressure but also amount of each substance in the system.
where,
is the amount of component 1 and 2 in the system.
Partial molar Gibbs free energy : The partial derivative of Gibbs free energy with respect to amount of component (i) of a mixture when other variable are kept constant are known as partial molar Gibbs free energy of
component.
For a substance in a mixture, the chemical potential is defined as the partial molar Gibbs free energy.
The expression will be:
where,
T = temperature
P = pressure
is the amount of component 'i' and 'j' in the system.