On the impedance of galvanic cells—XVI The impedance of the dropping mercury electrode in aqueous 1 M KCl with K+ discharge

Abstract

The discharge of K+ ions at the dropping mercury electrode (dme) in 1 M KCl solution at 25°C has been studied by means of analysis of the electrode impedance at different frequencies, using the complex plane method. It is shown that the electrode reaction is almost entirely diffusion-controlled, but a slight influence of activation polarization on the faradaic impedance can be detected at potentials between −1.95 and −2.0 V(sce). The heterogeneous rate constant ksh is estimated as ca 0.7 cm/s. Values of the double layer differential capacitance in the potential region where the electrode reaction occurs are calculated. Special attention is given to the inaccuracy of the results inherent in the method.