Determination of the first appearance of undissociated perchloric acid in aqueous solution from acidity-function data

Abstract

Attempts have been made to calculate the first appearance of undissociated perchloric acid in aqueous solutions from H₀ data and water activities using the hydration models for the proton suggested by Högfeldt and by Wyatt. The results seem to indicate this to be at about 3·5M. The calculations also bear out the importance of considering successive hydration equilibria of the proton when relating H₀ with the constitution of concentrated solutions of strong acids. Attempts to calculate degrees of dissociation for the acid gave low values in the most successful cases, and the implications of this are discussed.