Theoretical Analysis of Polarographic Waves. I. Reduction of Simple Metal Ions

Abstract

Abstract In the present paper, the general equation of the instantaneous diffusion current has been derived by taking into account the expansion of the mercury drop with the same accuracy as Ilkovic’s equation. Then, the general expression of the current-voltage curve for the reduction of simple metal ion has been given and its characteristics discussed upon being divided into three cases, i.e. reversible, irreversible and “quasi”-reversible. Reversible waves are given by electrode processes for which the value of ks is larger than 2×10−1 cm./sec., and on the other hand, irreversible waves are observed when the value of ks is smaller than 4×10−6cm./sec. In the irreversible case, it has been shown that the rate constant kj0 and the transfer coefficient α can be calculated from the observed values of the half-wave potential and the tangent of log-plot, respectively. At last, the equation of the current-voltage curve due to the reduction of organic substance has been derived. Addendum.—Recently J. Koutecky7) reported a theoretical treatment of the instantaneous and mean diffusion current for any point along the wave, in which the present diffusion problem was solved by an other method. The present work has been independently carried out.