Electrochemical oscillations on polarographic I-t curves in bromate solutions

Abstract

Polarographic I-t curves obtained with a dropping mercury electrode in solutions of sulphuric acid and bromate ions show oscillations in the region of positive potentials. These are related with the formation of Hg(II) bromate as anodic oxidation product, which is in turn reduced to Hg(I) bromate forming a passivating layer on the Hg electrode. The layer is mechanically disrupted during growth of the drop, whereby the electrode is reactivated and the process goes on giving rise to current oscillations.