Potentiometric study of the protonation equilibria of tartaric acid in aqueous sodium perchlorate solutions at 25 °C. Construction of a thermodynamic model

Abstract

The protonation equilibria of the tartrate ion have been studied using an automated potentiometric system. The temperature was kept constant at 25 °C and the ionic strength was 0.5, 1.0, 2.0 and 3.0 mol dm^–3 in NaClO₄. The experimental constants, obtained at different ionic strengths, were correlated by means of the modified Bromley theory and the thermodynamic protonation constants found to be log °β₁= 4.36 ± 0.02 and log °β₂= 7.36 ± 0.02. The possibility of the formation of mixed sodium species is also discussed.