On the impedance of galvanic cells XXII. Determination of the parameters of the double-layer impedance from the electrode impedance and the electrocapillary curve in the case of specific

Abstract

The electrode impedance in the case of specific adsorption of the electroactive species is discussed, critically applying the charge separation model of Delahay. Comparison with experiments performed with the In3+/In(Hg) couple in 1 M KCNS, comprising impedance, chronopotentiometric and surface-tension measurements, is given. An improved theory of the relation between surface tension and double-layer parameters is presented, leading to a better agreement with experiment. Consistent values are obtained for the surface excess of In3+.

It is shown that the linear relation between the value of thè double-layer capacity and Tl+ concentration that has been found earlier at low concentrations, also holds for concentrations up to 2 mM.

The consequences of the application of a modified treatment given by Reinmuth, are discussed.