Effect of Sodium Dodecyl Sulphate on the Kinetics of Reaction between Persulphate and Iodide Ions

. The kinetics of the reaction between potassium persulphate and potassium iodide has been studied iodometrically in aqueous solutions of sodium dodecyl sulphate (SDS) at various surfactant concentrations. It is observed that from low concentrations up to the c.m.c, the surfactant behaves like a normal electrolyte exhibiting primary kinetic salt effect. In presence of micelles it is observed that rate constant decreases with increase of ionic strength between cmc and 32 m mol dm of SDS and at very high concentrations of SDS the reaction rate increases slowly in keeping with the fact that owing to micellisation the concentration of monomeric SDS increases slowly with increase in the total concentration of SDS.