Gibbs’ Free Energy and Cell Potential or Electromotive Force [EMF]

Gibbs’ free energy change ∆G^Ꝋ is used to account for the spontaneity of a chemical reaction, while cell potential is the driving force behind the movement of electrons in a cell.

Note the following; when

i. ∆G^Ꝋ is negative, EMF [E^Ꝋ] is a positive reaction, is spontaneous.

ii. ∆G^Ꝋ is positive, EMF [E^Ꝋ] is a negative reaction. Reaction non-spontaneous

iii. ∆G^Ꝋ is zero, EMF [E^Ꝋ] is zero. Reaction is at equilibrium.

Therefore, the precise relationship between ∆G^Ꝋ and E^Ꝋ for a reaction in which a known mole of electrons move from anodeAn anode is an electrode of a polarized electrical device through which conventional current enters the device. It is the positive part of electrolytes where oxidation takes place. More to cathodeA cathode is the electrode from which a conventional current leaves the electrolyte. It is the negative part of the cell where reduction takes place. More is;