What is the relationship between Gibbs free energy of the cell reaction in a galvanic cell and the emf of the cell? When will the maximum work be obtained from a galvanic cell?
If concentration of all reacting speciesis unity, then Ecell = E0cell and G0 = -nFE0cell
where, G° is standard Gibbs energy of the reaction E0cell = emf of the cell nF = charge passed
If we want to obtain maximum work from a galvanic cell then charge has to be passed reversibly. The reversibly work done by a galvanic cell is equal to decrease in its Gibbs energy.
G = — nFE0cell
As Ecell is an intensive parameter but G is an extensive thermodynamic property and the value depends on n.
For reaction, Zn (s) + Cu2+ (aq) Zn2+ (aq) + Cu(s) in a galvanic cell,
