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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

1991

Earth Sciences

Department of Earth and Atmospheric Sciences: Faculty Publications

Oxalic acid; ethanedioic acid; dissociation constants; thermodynamics; potentiometry; ionic strength.

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Full-Text Articles in Physical Sciences and Mathematics

Dissociation Quotients Of Oxalic Acid In Aqueous Sodium Chloride Media To 175c, Richard Kettler, Donald A. Palmer, David J. Wesolowski Jan 1991

Dissociation Quotients Of Oxalic Acid In Aqueous Sodium Chloride Media To 175c, Richard Kettler, Donald A. Palmer, David J. Wesolowski

Department of Earth and Atmospheric Sciences: Faculty Publications

The first and second molal dissociation quotienls of oxalic acid were measured potenliometrically in a concentration cell filled with hydrogen electrodes. The emf of oxalic acid-bioxalate solutions was measured relative to an HCI standard solution from 25 to 125°C over 25° intervals at nine ionic strengths ranging from 0.1 to 5.0 molal (NaCl). The molal dissociation quotients and available literature data were treated in the all anionic form by a five-term equation that yielded the following thermodynamic quantities at infinite dilution and 25°C: logKIa = -1.277±0.010, ΔHl̊a = -4.1± 1.1 kJ-mol-1, ΔSl̊a = 38±4 J-K …