Hypochlorit6 and chlorite react in solution to form chlorate and therate of the reaction varies with the, pH of the solution.We elucidated the mechanism of this reaction and determined the rate constants of two principal reaction steps.The hypo chlorous.acid, which is produced through the hydrolysisof hypechlorite, reacts with the chlorite ion and liberates chlorine dioxide in the 1st step. ln the 2 nd step, the chlorine dioxide reacts with the hypechloriteien to form chlorate.The rate of reaction in the 1st step depends greatlyon the pH of the solution, and the ncreasb.of pH retagds the liberation of chlorin dioxide, resulting-in a decrease in the over all reactlosn rate.Therate equations for both steps are of 3 rd order. The rate constants are 1.9 105 and4.QxIO (molm2.IS.minmi) for the 1st and 2nd step, respectively.Since the reaction system studied contained hypochlorite, hypochlorous acid, ehlerite, chlorate and chlorine dioxide, we established a satisfactory method for the determiRation of these eomponents, before starting above exPeriments,