Dissociation constants and limiting conductances of organic acids in water

Determination of the dissociation constants of organic acids in aqueous solutions by the conductometric method during a period of nearly 120 years is discussed. Electrical conductivities available in the literature were reexamined to yield a reliable and consistent set of the limiting conductances of organic anions λ⁰ and the dissociation constants K of 250 organic acids at T = 298.15 K. Also, presented are coefficients of the Quint-Viallard conductivity equation which permit to evaluate conductances of these acids in dilute solutions (c ≤ 10^-2 mol·dm^-3). The experimental conductances were analyzed in terms of dissociation steps of carboxylic acids, the Onsager conductivity equation for neutral sodium or potassium salts, the Quint-Viallard conductivity equation for unsymmetrical electrolytes (monobasic and polybasic acids) and the Debye-Hückel equation for activity coefficients.