Redox properties of cobalt(III) mixed ligand complexes. II. Redox titration of some organic and inorganic substances potentiometrically

A stable solution of (cobalt(III)(salen))₂O₂ was prepared under optimum conditions for its use for the potentiometric determination of xylenols, hydroquinone, sodium thiosulfate, and sodium metabisulfite, by iodide reduction of unreacted cobalt(III) complex and back titrating excess iodide with mercury(II) using silver amalgum and SCE combination. The possible schemes for the course of the redox reactions were suggested. The procedure was also evaluated in comparison with those mentioned in the literature.