Protonation Equilibria at Elevated Temperatures and Investigations on Thermodynamics Parameters for Ascorbic Acid at an Ionic Strength of 1.0 mol·dm−3NaClO4

The protonation equilibria for ascorbic acid at an ionic strength of 1.0 mol·dm −3 NaClO 4 medium have been studied pH-potentiometrically. The protonation constants of ascorbic acid and the thermodynamic functions (Δ G, Δ H, and Δ S ) for the successive and overall protonation processes of ascorbic acid have been derived at three different temperatures. A detailed thermodynamic analysis of the effects of temperature and ascorbic acid concentration influencing the protonation processes is presented and discussed to determine the factors which control these processes.