Limits of Acidity Constants Validity of Diprotic Acids with K1/K2< 10~4 Calculated from Potentiometric Data

摘要

Algorithms of acidity constants of diprotic acids have been established on the grounds of a global protonation of active centers within the molecule of these chemical species. The values of the acidity constants, calculated from the measured pH values, have not been altered by the involvement of the ampholytes as macrospecies, compared to two other macrospecies: the diprotic acid and the neutral salt of diprotic acid. The validity of these constants is not absolute, because they were influenced by energies, resulted from interactions, determined by the ampholyte division in two microspecies, differentiated according to the occupied protonation center.