Question

Write a short note on polarisation and decomposition potential

Answer 1

Taking the case of the electrolysis of water, with smooth platinum electrodes, as a typical example, the fundamental components of the cell or bath voltage are interpreted. Thereupon revised definitions are proposed and these are discussed at length. Finally the following recommendations are submitted: 1. The “equilibrium reaction potential” is preferably used to refer to the potential based on the free energy of the process. 2. The “decomposition potential” is the minimum potential required for continuous electrolysis. 3. The term “polarization” includes all departures of the potential from the equilibrium potential, and is a measure of irreversibility (excluding IR drop) regardless of whether the products are solid, liquid, or gaseous. 4. The term “overvoltage” preferably refers to the minimum polarization required for any electrode process to occur at an appreciable rate under given conditions.