Abstract
The kinetics of the oxidation of S2O32− by ClO2− have been studied in aqueous alkaline solution at 900C using classical titrimetric methods to follow the course of the reaction. The reaction takes place according to the stoichiometry S2O32− + 2ClO2− + 2OH− = 2SO42− + 2Cl− + H2O even in large S2O32− excess. There is some indication of a complex reaction pattern, but 70% of the ClO2− disappearance can be best described by the autocatalytic rate equation ‐d[ClO2−]/dt = k[S2O32−] [ClO2−] [H+] with k = (1.3 ± 0.2) ×108 M−2 sec−1. The mechanism is explained by postulating nucleophilic attack of S2O32− on HClO2 to form a chlorine‐containing intermediate.