ABSTRACT
All chemical reactions, in which products form from reactants, involve changes in the state of oxidation, or valence state, of some or all of the participating atoms. Changes in the valence state of an element are caused by the addition or removal of electrons. The change in free energy is thus a manifestation of the energetics of electron transfer. The driving force for the transport of electrons along 'a' is manifested as an electric voltage. Electric voltage can be measured by placing an external opposing voltage in the circuit 'a' and adjusting this voltage until no electric current flows, at which point the electrochemical reaction ceases. At this point, the external voltage exactly balances the voltage generated by the electrochemical system. The asymmetric forces at the interface between the metal and the electrolyte cause the rearrangement of the solvent dipoles and the charged species in such a manner that the electrolyte side of the interface becomes electrically charged.
