The thermodynamic dissociation constant of acetic acid in a mixed solvent

The classical theory of acid and base dissociation, characterised acids by their ability to split off hydrogen ions, and bases by their ability to split off hydroxyl ions when dissolved in water. These views were based on the Arrhenius theory of dissociation of electrolytes in water, and did not explain the complementary yet opposite properties of acids and bases, nor did it extend the treatment beyond aqueous solutions. For example, pure hydrochloric or acetic acids would not be considered as acids in themselves as hydrogen ions are not detectable in them in the pure state. The classical theory is, therefore, inconsistent, in so far as the description acid or base, is only allowed after the addition of a second substance, namely water. The role the water played in the mechanism was for a long time unrecognised