Standard electrode potential to produce an electric potential, Gibbs free energy Δ"G"° must be negative, in accordance with the following equation: where "n" is number of moles of electrons per mole of products and "F" is the Faraday constant, ~96485 C/mol. As such, the following rules apply: Thus in order to have a spontaneous reaction (ΔG° < 0), "E"° must be positive, where: where "E"° is the standard potential at the anode and "E"° is the standard potential at the cathode as given in the table of standard electrode potential. Standard electrode potential In electrochemistry, it is defined as the measure of the
Half-cell a standard hydrogen half-cell, connected by a salt bridge. The standard hydrogen half-cell: The half-cells of a Daniell cell: Standard electrode potential (data page) Half-cell A half-cell is a structure that contains a conductive electrode and a surrounding conductive electrolyte separated by a naturally occurring Helmholtz double layer. Chemical reactions within this layer momentarily pump electric charges between the electrode and the electrolyte, resulting in a potential difference between the electrode and the electrolyte. The typical anode reaction involves a metal atom in the electrode dissolved and transported as a positive ion across the double layer, causing the electrolyte to