Irreversible interactions between metals and electrolytes

Abstract

It is shown kinetically that when a finite metal is dipped into an infinite electrolyte initially not containing ions of the metal, equilibrium cannot be reached unless the metal dissolves completely. The initial absolute rate of spontaneous dissolution is calculated. It is shown how that rate is radically retarded if a double layer is built up by the dissolution which is strong enough to saturate the dielectric constant of the solution at the interface. The requisite strength of the double layer as well as the time of its formation are estimated. However, dielectric saturation at the interface of some metals does not set in before the double layer reaches a strength leading to spontaneous evolution of hydrogen gas. A general condition of stability is formulated which singles out such cases, and rates of metal dissolution with hydrogen evolution are calculated for these cases, including the time intervals between dipping and the commencement of gas evolution.