Calorimetric Heats of Ionization of Aqueous Benzoic Acid from 5–100 °C and Derived Thermodynamic Quantities

Abstract

We have made calorimetric measurements at 5.0, 12.5, 25.0, 40.0, 50.0, 65.0, 75.0, 85.0, and 100 &([a-z]+);C that lead to values of ΔH⁰ of ionization of aqueous benzoic acid at each of these temperatures. These ΔH⁰ values have been used with pK = 4.204 at 25.0 °C for calculation of pK values from 5 to 100 &([a-z]+);C and also ΔC_p⁰ of ionization values over this range. Usefulness of various extrapolation functions for ΔH⁰, ΔC_p⁰, and pK up to 225 °C has been investigated.