Solvation Behavior of Phthalic Acid in Triple Distilled Water + Methanol at Various Temperatures: Insight from Shedlovsky and Kraus–Bray Models

Abstract—The present research article focuses on the influence of solvation species of phthalic acid in triple distilled water + methanol system at four different solution temperatures (293, 303, 313, and 323 K). The specific conductance was examined on the studied systems. Shedlovsky and Kraus–Bray models were used to determine the limiting molar conductance (${{\lambda }}_{{\text{m}}}^{0}$), association constant (K_a), and dissociation constant (K_c). The thermodynamic parameters such as activation energy (E_a), change in entropy (∆S_a), change in enthalpy (∆H_a), and change in free energy (∆G_a) of association process were also screened. The limiting molar conductance (${{\lambda }}_{{\text{m}}}^{0}$) was found to increase with an increase in the solution temperature and decreases with a rise in the methanol (co-solvent) in the water–phthalic acid system. Quantum chemical studies clearly confirm the electron donation property of phthalic acid.