title: Revisiting the kinetics and mechanism of the tetrathionate-hypochlorous acid reaction in nearly neutral medium.
abstract: The tetrathionate-hypochlorous acid reaction has been investigated in nearly neutral medium at I = 0.5 M ionic strength and T = 25.0 +/- 0.1 degrees C in dihydrogen-phosphate-hydrogen-phosphate buffer by UV-vis spectrophotometry. In excess of hypochlorous acid, the stoichiometry was found to be S(4)O(6)(2-) + 7HOCl + 3H(2)O --> 4SO(4)(2-) + 7Cl(-) + 13H(+), but in excess of tetrathionate colloidal sulfur precipitates. On the basis of the simultaneous evaluation of the kinetic curves, a nine-step kinetic model with four fitted and five fixed rate coefficients is proposed. Analogous oxidation reactions of tetrathionate are also compared and discussed.
authors.affiliation: Department of Inorganic Chemistry, University of Pécs, Ifjúság útja 6., H-7624 Pécs, Hungary.
authors.forename: Dénes
authors.initials: D
authors.lastname: Varga
authors.forename: Attila K
authors.initials: AK
authors.lastname: Horváth