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Kinetics of Iodous Acid Disproportionation
Author(s) -
Schmitz Guy,
Furrow Stanley D.
Publication year - 2013
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20791
Subject(s) - chemistry , disproportionation , autocatalysis , reaction rate constant , sulfuric acid , scavenger , kinetics , medicinal chemistry , inorganic chemistry , radical , organic chemistry , catalysis , quantum mechanics , physics
The iodous acid disproportionation is autocatalytic, and it is not easy to measure the rate constant of the step 2IO 2 H → IO 3 − + IOH + H + separately. Hg(II) was used previously to suppress the autocatalytic pathway, but this method presents difficulties discussed in this work. A more effective method is the use of crotonic acid, an effective IOH scavenger. It suppresses side reactions, and a purely second‐order rate law is obtained. The rate constant decreases from 5 to 0.2 M −1 s −1 when the sulfuric acid concentration increases from 0.08 to 0.60 M. The observed decrease could be explained if IO 2 − reacts faster than IO 2 H. This may have consequences for the mechanism of the oscillating Bray–Liebhafsky reaction.