An improved chemical model for the quantitative description of the front propagation in the tetrathionate–chlorite reaction

Abstract

It is experimentally proven that the stoichiometry of the tetrathionate–chlorite reaction is 2S₄O²⁻₆ + 8½ClO⁻₂ + 6H₂O = 8SO²⁻₄ + ClO⁻₃ + 7½Cl⁻ + 12H⁺ near 1 : 4 molar ratio of the reactants. Re-evaluation of the previously measured front velocity—concentration curves also shows that this stoichiometry along with both the rate equation r = (1.6 × 10⁵ M⁻³ s⁻¹ [H⁺]² + 3.6 × 10⁷ M⁻⁴ s⁻¹ [H⁺]³)[S₄O²⁻₆][ClO⁻₂]and the protonation processes existing in the present system allow us to describe the front velocity as a function of the initial concentration of the reactants quantitatively. Some consequences detailed in the conclusions may concern not only uniquely the tetrathionate–chlorite reaction but any front propagation study including H⁺ as an autocatalyst.