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
Reference electrode Reference electrode A reference electrode is an electrode which has a stable and well-known electrode potential. The high stability of the electrode potential is usually reached by employing a redox system with constant (buffered or saturated) concentrations of each participant of the redox reaction. There are many ways reference electrodes are used. The simplest is when the reference electrode is used as a half cell to build an electrochemical cell. This allows the potential of the other half cell to be determined. An accurate and practical method to measure an electrode's potential in isolation (absolute electrode potential) has yet to