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Remarks on the evaluation of thermodynamic data for sulfate Ion protonation

Hefter, G. and Gumiński, C. (2019) Remarks on the evaluation of thermodynamic data for sulfate Ion protonation. Journal of Solution Chemistry, 48 (11-12). pp. 1657-1670.

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A thorough search of the scientific literature under the auspices of the IUPAC Sub-Committee on Solubility and Equilibrium Data (SSED) has identified and compiled quantitative thermodynamic data for the first sulfate protonation step from about 270 papers, reports, books and electronic databases. A critical evaluation of these sources using well-defined criteria has rejected about half of them. The remaining (‘accepted’) data reveal that the standard state values of the first protonation constant of the sulfate ion, Ko1, corresponding to the equilibrium: SO2−4(aq)+ H+(aq)⇌HSO−4(aq) at infinite dilution, are known to good levels of accuracy up to ~ 250 °C. However, at higher temperatures, and at all temperatures in the presence of added electrolytes, the equilibrium constant values are much less certain. The corresponding values for the enthalpy (ΔrHo1), entropy (ΔrSo1) and isobaric heat capacity (ΔrCop,1) changes are also moderately well determined at near-ambient temperatures but are much more poorly defined both at higher temperatures and in the presence of even modest concentrations of added electrolytes. Comments on a number of aspects of the data and their evaluation are provided.

Item Type: Journal Article
Murdoch Affiliation(s): Chemistry and Physics
Publisher: Springer Netherlands
Copyright: © 2019 Springer Science+Business Media, LLC, part of Springer Nature
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