Collect. Czech. Chem. Commun. 1988, 53, 1156-1161

Electrochemical oscillations on polarographic I-t curves in bromate solutions

Anna Olexová and Ľudovít Treindl

Department of Physical Chemistry, Comenius University, 842 15 Bratislava


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.