The kinetics of the bromate–sulfite reaction system

The kinetics of the reaction between BrO₃⁻ and sulfite was studied by measuring the concentrations of [Br⁻] and [H⁺] both in buffered and in unbuffered solutions. A mechanism was applied for simulation of the experimental observations. Rate constants k₁=(0.027±0.004) M⁻¹s⁻¹ and k₂=(85±5) M⁻¹s⁻¹ were determined for the following reactions: halign{hfill $#$hfill &hfillqquadqquad #cr 3 rm HSO_{3}!^{-}+BrO_{3}!^{-}longrightarrow 3 SO_{4}!^{2-}+Br^{-}+3 H^{+}& (1)cr 3 rm H_{2}SO_{3}(hbox{or} SO_{2.}hbox{aq})+BrO_{3}!^{-}longrightarrow 3 SO_{4}!^{2-}+Br^{-}+6 H^{+}& (2)cr } Rate constant k₁ was obtained directly from the experimental results on unbuffered reactions, where Reaction (1) was predominant. Rate constant k₂ was obtained by computer fitting of [Br⁻] to the experimental values for buffered reactions, where the rate of Reaction (2) was about four times higher than that of Reaction (1). © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 869–874, 1998