Medium Effects on Dissociation Constants of Maleic and Malonic Acids in Acetone–Water Binary Mixtures. A Thermodynamic Study

Abstract

The pK 1 and pK 2 values of maleic and malonic acids were determined by using a precise EMF method in acetone-water media of varying solvent compositions at different temperatures. The thermodynamic functions of dissociation (∆H • , ∆G • , and ∆S • ) have been computed, discussed and analyzed in terms of solute-solvent interactions. The pK values have been correlated with both the mole fraction of the organic solvent and the distance between the dicarboxyl groups in each acid.

Thermodynamic determination of solvation potentials of divalent metal chlorides (MCl2) in iso–dielectric media by EMF measurements

“…The 'short-range' primary solvating effect as dictated by the chemical nature of the solvents is hardly noticeable [8,9]. It makes the understanding of the solvent effect inadequate, as is evident from recent studies [10][11][12]. In view of these inconclusive investigations and in continuation of the earlier studies of the solvent effect on ion-solvent transfer equilibrium in aqueous co-solvents [8,9], we have extended the same to some iso-dielectric solvent systems.…”