Determination of pK(a) of acetic and benzoic acids in pyridine

The pK(a)'s of acetic acid and benzoic acid in pyridine as solvent are found to be 10.1 and 9.8, respectively, at 25 degrees . These results are based on measurements of hydrogen ion activities in mixtures of the acids and their tetrabutylammonium salts. Supplementary studies of differential vapour pressure characteristics of solutions of the acids and the acid-salt mixtures, and conductance of tetrabutylammonium benzoate solutions are also incorporated.