The Kinetics and Mechanism of the Chlorine Dioxide - Iodide Ion Reaction

István Fábián, Gilbert Gordon

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Abstract

The oxidation of iodide ion by chlorine dioxide has been studied by stopped-flow techniques at I = 1.0 M (NaClO4). The following two-term rate law was confirmed for the reaction: -d[ClO2]/dt = kI[ClO2][I-] + kII[ClO2][I-]2. The rate constants at 298 K and the activation parameters are kI = (1.87 ± 0.02) × 103 M-1 s-1, ΔHI = 35.4 ± 0.7 kJ/mol, ΔSI = -63.5 ± 2.3 J/(mol K), kII = (1.25 ± 0.04) × 104 M-2 s-1, ΔHII = 36.7 ± 1.3 kJ/mol, ΔSII = -43.2 ± 4.6 J/(mol K). Both the second- and third-order paths are interpreted in terms of an outersphere electron-transfer mechanism. The calculations based on the Marcus theory yield kI = 1358 M-1 s-1 for the second-order path.

Original languageEnglish
Pages (from-to)2494-2497
Number of pages4
JournalInorganic Chemistry
Volume36
Issue number12
Publication statusPublished - Dec 1 1997

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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