KINETICS OF THE UNCATALYZED AND CU(II)-CATALYZED DECOMPOSITION OF SODIUM-HYPOCHLORITE

Rate equations for the decomposition of aqueous alkaline NaClO were in tegrated with inclusion and exclusion of the effects of first-order Cu (II) catalysis, yielding new time-dependent expressions for [ClO-], ev olved oxygen, and [ClO3-]. Using a gravimetric technique, uncatalyzed and Cu(II)-catalyzed rate constants for oxygen evolution and CIO- loss were measured and consolidated with previous results. Activation para meters of the uncatalyzed rate-limiting reactions to ClO2- and oxygen could be approximated as linear functions of ionic strength mu, allowi ng estimation of the respective rate constants k1 and k(o) at 40-70-de grees-C in the mu range 2-5. For Cu(II) catalysis at 40-70-degrees-C i n the mu range 4.2-4.7, E(a), DELTAH(double dagger), and DELTAS(double dagger) values of 83 300 J g-mol-1, 80 550 J g-mol-1, and -14.6 J K-1 g-mol-1, respectively, were derived from previous and current results , allowing k(Cu) also to be estimated and used in the system of integr ated equations.