New indicating system: twin electrodes, at zero current

Abstract

A mechanism for the new indicating system “twin electrodes, at zero current”, is proposed. In the titration cell, even with efficient stirring, regions of different liquid velocity arise, resulting in different thicknesses of the diffusion layers at the electrodes placed in the solution. This causes the electrodes to respond at different rates to changes in the solution during the titration. The potential change of each electrode is given by an “S”-shaped curve. Owing to the small difference in their rates of response, a sharp peak is obtained when their potential difference is recorded throughout the titration.