Electron Transfer Between Hexacyanoferrate (III) and Thiosulphate‐a Kinetic and Mechanistic Study in Aqueous Alkaline Media

Kinetics of oxidation of thiosulphate by hexacyanoferrate (III) in aqueous alkaline media follow a rate‐expression, «span» where K h and k 2 respectively represent the hydrolysis constant of thiosulphate and the self‐decomposition constant of acid thiosulphate ion; the K h and k 2 values have been respectively computed to be (1.09±0.1)x10 −3 mol dm −3 and (6.13±0.4)x10 −7 s −1 at 318 K and 0.32 mol dm −3 of ionic strength in alkaline medium. The mechanism is interpreted in terms of a spontaneous change of thiosulphate in a rate‐determining step, followed by a rapid reduction of hexacyanoferrate (III).