Premium
Electron transfer between trans ‐dihydroxotetraoxoosmate(VIII) and thiosulfate. A kinetic study in aqueous alkaline media
Author(s) -
Panda Rama Krushna,
Neogi Gautam,
Ramaswamy D.
Publication year - 1981
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.550131002
Subject(s) - chemistry , thiosulfate , reaction rate constant , electron transfer , tetrathionate , aqueous solution , kinetics , decomposition , kinetic energy , equilibrium constant , aqueous medium , inorganic chemistry , sulfur , organic chemistry , physics , quantum mechanics
The kinetics of oxidation of thiosulfate to tetrathionate by trans ‐dihydroxotetraoxoosmate(VIII) in aqueous alkaline media have been studied. The oxidation follows a rate expression\documentclass{article}\pagestyle{empty}\begin{document}$$ - \frac{{d[{\rm Os(VIII})]}}{{dt}} = k3{\rm K}_{OS} {\rm K}_2 [{\rm S}_2 {\rm O}_3^{2 - }][{\rm Os(VIII})](1 + {\rm K}_{os} {\rm K}_2 [{\rm S}_2 {\rm O}_3^{2 - }])^{ - 1} $$\end{document}where K Os is the formation constant of trans ‐dihydroxotetraoxoosmate (VIII), and K 2 and k 3 , respectively, represent the formation constants of the intermediate complex involving Os(VIII) and S 2 O 3 2−and its decomposition constant. The K Os , K 2 , and k 3 values have been computed to be (19.5 ± 3) dm 3 /mol, (6.12 ± 0.5) and (3.32 ± 0.3) × 10 −1 dm 3 /mol s at 303 K, and I = 0.32 mol/dm 3 , respectively. The rate law is consistent with a mechanism envisaging the equilibrium formation of an intermediate complex involving Os(VIII) and S 2 O 3 2− , followed by a rate‐determining decomposition of the complex with concomitant electron transfer.