Why Physicochemical Properties of Aqueous Solutions of Various Compounds Are Linearly Interrelated

Document Type


Publication Date


Digital Object Identifier (DOI)



Analysis of physicochemical properties, such as water activity, osmotic coefficients, surface tension, viscosity, and relative permittivity, of aqueous solutions of different inorganic salts, organic compounds, and polymers shows that these properties are linearly interrelated and this interrelationship may be described as: Yi1(ci1) = k1 + k2Yi2(ci2) + k3Yi3(ci3), where Yi1(ci1), Yi2(ci2), and Yi3(ci3) are properties of aqueous solutions of individual compounds 1, 2, and 3 at the same ith concentration i of each compound (ci1 = ci2 = ci3); k1, k2, and k3 are constants. The relationship holds for various concentrations of compounds provided properties of aqueous solutions of the individual compounds are compared at the same concentration of each compound. Similar interrelationships are established also between different properties of aqueous solutions of any given compound. It is suggested that the reason for these relationships is that all physicochemical properties of aqueous solutions of any compound display different aspects and peculiarities of intermolecular water-water interactions affected by the presence of the compound, its nature, and concentration. The different types of water-water interactions in aqueous solutions may be quantified with the solvatochromic dyes. The solvent dipolarity/polarizability, π*, hydrogen bond donor acidity, α, and hydrogen bond acceptor basicity, β of water reported previously for aqueous solutions of organic compounds and polymers as well as those obtained for solutions of inorganic salts are linearly interrelated likely due to the cooperativity of intermolecular interactions in water. It is shown that any physicochemical property of aqueous solution of a given salt, organic compound, or polymer may be described by linear combination of two solvent features, π* and α, or in some cases by a single solvent feature. This fact explains the reason for the existence of the aforementioned linear interrelationships between the physicochemical properties of aqueous solutions of different compounds.

Was this content written or created while at USF?


Citation / Publisher Attribution

Journal of Molecular Liquids, v. 221, p. 116-123