A Study of the Ferrous-Ferric System in Phosphoric Acid

Abstract

It is the purpose of this paper to show the effect of orthophosphoric acid on the oxidation-reduction potential of the ferrous-ferric system by using methods of procedure and apparatus that are easily reproducible under laboratory conditions. |In the media of various concentrations of orthophosphoric acid, the potential of the ferrous-ferric system is depressed far below the standard value. This depression is due principally to two reactions: (1) the formation of complex ions by the combination of ferric ion with the orthophosphate ion; and (2) complex ferric hydroxide ions resulting from hydrolysis.