THE ROLE OF SINGLE-PHASE FREE-CONVECTION IN MASS-TRANSFER AT GAS EVOLVING ELECTRODES .1. THEORETICAL

The catalogue of known mass transfer mechanisms acting at gas evolving electrodes has to be extended by a mechanism which has obviously been ignored so far. Under certain conditions, free convection owing to density gradients within the liquid phase (single-phase convection) exerts the controlling effect on mass transfer. Generally, the mechanism competes with other mass transfer mechanisms which have been investigated for a long time and are rather well understood. Available mass transfer equations for these mechanisms are extended to fit the special conditions of gas evolving electrodes. A general mass transfer equation for single-phase free convection is derived.