For the redox reaction Ox + z e → Red, Q r = [ R e d ] [ O x ] , and we have: E = E ⊖ ⊖ − − k T z e ln ⁡ ⁡ [ R e d ] [ O x ] = E ⊖ ⊖ − − R T z F ln ⁡ ⁡ [ R e d ] [ O x ] = E ⊖ ⊖ − − R T z F ln ⁡ ⁡ Q r .