An analysis of electrical conductances of aqueous solutions of polybasic organic acids. Benzenehexacarboxylic (mellitic) acid and its neutral and acidic salts.

A general approach is proposed to analyze electrical conductivities in aqueous solutions of polybasic organic acids. Experimental conductivities are examined in the context of dissociation and hydrolysis reactions by applying the Quint-Viallard conductivity equations and the Debye-Hückel equations for activity coefficients. The proposed numerical procedure is illustrated by the case of benzenehexacarboxylic (mellitic) acid and its neutral and acidic salts. From conductivity measurements of mellitic acid and its salts, performed in dilute aqueous solutions in the 278.15-308.15 K temperature range, the limiting conductances of mellitic anions, lambda(0)(1/jH(6-j)Mel(-j), T), j = 1, 2, 3, 4, 5, 6 are determined.