A Chronocoulometric Study of the Adsorption of Anthraquinone Monosulfonate on Mercury

Abstract

The quantity of anthraquinone monosulfonate (AQS) anions specifically adsorbed on mercury electrodes has been determined by chronocoulometry in fluoride, thiocyanate, nitrate, and p‐toluene sulfonate electrolytes. In all electrolytes but fluoride competitive adsorption of AQS and the supporting electrolyte anion occurred. The adsorption produced very little change in the charge on the mercury or, therefore, on the amount of specifically adsorbed anions from the supporting electrolytes. The adsorbed anthraquinone monosulfonate anions produced large changes in the potential at the outer Helmholtz plane which were detected by the resulting changes in the rates of two irreversible electrode reactions.