KINETICS STUDY OF THE DISPROPORTIONATION OF THE IODOUS ACID IN AQUEOUS SULFURIC ACID SOLUTION

Smiljana Marković; Biljana Petrović

doi:10.5937/univtho6-10474

Smiljana Marković Faculty of Technical Science, University of Priština, Kosovska Mitrovica
Biljana Petrović Faculty of Science, University of Kragujevac, Kragujevac

DOI: https://doi.org/10.5937/univtho6-10474

Abstract

In this paper we reported the kinetics of the disproportionation reaction of iodous acid (HOIO) in aqueous sulfuric acid solutions (0.18 mol/dm³) studied by spectrophotometrical measurements of the absorbance at suitable wavelength. The changes of the absorbance were caused because the absorbing I₂ molecule species were generated during the reaction. The disproportionation rate constants are calculated at the temperature range between 285 and 303 K with average values: k²⁸⁵ = (0.90 ± 0.08) dm³mol^-1s^-1, k²⁹¹ = (1.10 ± 0.10) dm³mol^-1s^-1, k²⁹⁸ = (1.30 ± 0.07) dm³mol^-1s^-1and k³⁰³ = (1.50 ± 0.10) dm³mol^-1s^-1, respectively. The corresponding activation energy was determined, for the chosen temperature interval, by a graphical method. In addition, obtained value of activation energy is E_a = 38 ± 5 kJ/mol. The negative value of Gibbs energy change and other thermodinamical parameters show that is the disproportionation reaction thermodynamically feasible.

Keywords

iodous acid;disproportionation reaction;rate constants;activation energy.

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