A Comparison of the H_ and H0 Acidity Functions for Aqueous Hydrochloric Acid Solutions

H- acidity function measurements are reported for aqueous hydrochloric acid solutions using a series of phosphorus-containing acid indicators. The relationship between the H-, Ho, and activity (-log10f�C) function for this system was found to be given approximately by ����������������� �(Ho+H-) ≈ -log10f�CHCl A feature of the results is the weak acidity of concentrated hydrochloric acid solutions in respect of the ionization of a negatively charged base, in contrast to the strong acidity of such solutions in respect of the ionization of a neutral base.