Analysis of Viscometric and Conductometric Properties of l-Ascorbic Acid in Aqueous Potassium Chloride and Diammonium Hydrogen Phosphate

Abstract

In the present study, we report the experimental viscometric and conductometric properties of vitamins, namely, l-ascorbic acid (LAA), in aqueous and binary aqueous potassium chloride (KCl)/diammonium hydrogen phosphate (DAP) within the concentration range 0.01–0.15 mol kg^–1 at T = 293.15, 298.15, 303.15, 308.15, and 313.15 K. The experimentally obtained dynamic viscosity values and the molarity of solutions have been correlated according to the Jones–Dole equation to derive the Falkenhagen coefficient A, Jones–Dole viscosity B-coefficient, and temperature derivative of B-coefficient, i.e., (∂B/∂T). Free energy of activation for viscous flow per mole of solvent (Δμ₁^0#) and per mole of solute (Δμ₂^0#), entropy, and enthalpy of activation for viscous flow per mole of solvent (ΔS₂^0# and ΔH₂^0#, respectively) have also been computed. Conductometric parameters like molar conductance (Λ_m), Walden factor (Λ_m⁰η₀), thermodynamic parameters for ion association, and activation energy for charge mobility have been determined. These parameters were qualitatively correlated with changes in the structure of water that occurs when LAA interacts with KCl/DAP in aqueous media.