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

Abstract

H_- acidity function measurements are reported for aqueous hydrochloric acid solutions using a series of phosphorus-containing acid indicators. The relationship between the H_-, H_o, and activity (-log₁₀f±C) function for this system was found to be given approximately by                   ½(H_o+H_-) ≈ -log₁₀f±C_HCl 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.