Variations in the Composition of Bromine Water During Oxidation Reactions

A cubic equation has been derived that permits calculation of the composition of aqueous bromine solutions in terms of HOBr, BrO − , Br 2 , Br − 3 and Br − as a continuous function of the pH, the initial oxidant concentration and the mole fraction of oxidant consumed. The calculations were performed by computer for the pH range 0–14 at bromine concentrations ( c 0 ) of 10 −1 to 10 −7 M. Throughout the course of an oxidation at pH 0 and c 0 = 10 −4 , bromine water is pure Br 2 . No Br − 3 exists at c 0 < 10 −3 . In the pH range 4–6, dilute bromine solutions are pure HOBr (+ equimolar Br − ). For pH > 10, bromine water is pure BrO − , while at pH < 7, no BrO − is present. These conditions are unchanged during oxidant consumption.