Kinetic study of the oxidation of iodide by hexachloroiridate( IV ) in concentrated electrolyte solutions

Rate constants are reported for the oxidation of iodide by hexachloroiridate(IV) in various concentrated electrolyte solutions containing up to 6 mol dm–3 salt at 298.2 K. The conclusion is that the salt effects are mainly due to ion–solvent interactions. This is supported by considering the activity coefficients of the reaction participants, estimated by using the Stokes–Robinson hydration treatment. The study of kinetics at 333.2 K shows that the distinct behaviour of potassium nitrate seems related not only to the different structural character of this salt with respect to the rest of the electrolytes studied, but also to specific interactions which are operative favouring the reaction.