Kinetics of the reduction of the tetrahydroxyargentate(III) ion by sulphite in aqueous alkaline media
Document Type
Article
Date of Original Version
1-1-1989
Abstract
The reduction of Ag(OH)4- by sulphite ion to give silver(I) and sulphate in strong base has been studied by stopped-flow spectrophotometry. The reaction was found to fit a second-order rate law with a rate constant k = (9.1 ± 0.1) x 102M-1s-1 (T = 25°C, μ = 1.2 M). The estimated enthalpy and entropy of activation are 27 kJ mol-1 and - 153 J K-1 mol-1 respectively. Variation of rate with ionic strength is consistent with the interaction between mononegative Ag(OH)4- and dinegative SO32-. The redox reaction appears to proceed by a one-step oxygen atom transfer. Two kinetically indistinguishable pathways are discussed. The first involves initial attack of a sulphite oxygen at an axial silver(III) site. The second pathway involves initial interaction between sulphur(IV) and a bound hydroxyl. Sulphite oxidation by silver(III) is about 104 times faster than that of phosphite, while no reaction is observed with NO2-. © 1989.
Publication Title, e.g., Journal
Polyhedron
Volume
8
Issue
10
Citation/Publisher Attribution
Kirschenbaum, Louis J., Issifou Kouadio, and Edoardo Mentasti. "Kinetics of the reduction of the tetrahydroxyargentate(III) ion by sulphite in aqueous alkaline media." Polyhedron 8, 10 (1989). doi: 10.1016/S0277-5387(00)86527-4.