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Abstract:
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The nature of the diperiodatocuprate(III) (DPC) species present in aqueous alkaline medium has been investigated
by a kinetic and mechanistic study on the oxidation of iodide by DPC. The reaction kinetics were studied over the
1.0 ´ 10)3±0.1 mol dm)3 alkali range. The reaction order with respect to DPC, as well as iodide, was found to be
unity when [DPC] [I)]. In the 1.0 ´ 10)3±1.0 ´ 10)2 mol dm)3 alkali region, the rate decreased with increase in
the alkali concentration and a plot of the pseudo-®rst order rate constant, k versus 1/[OH)] was linear. Above
5.0 ´ 10)2 mol dm)3, a plot of k versus [OH)] was also linear with a non-zero intercept. An increase in ionic
strength of the reaction mixtures showed no e ect on k at low alkali concentrations, whereas at high concentrations
an increase in ionic strength leads to an increase in k. A plot of 1/k versus [periodate] was linear with an intercept in
both alkali ranges. Iodine was found to accelerate the reaction at the three di erent alkali concentrations employed.
The observed results indicated the following equilibria for DPC. |