Application of a multicomponent thermodynamic model to activities and thermal properties of 0-40 mol kg^-1 aqueous sulfuric acid from

A multicomponent mole-fraction-based thermodynamic model has been fitted to osmotic coefficients, electromotive force measurements, degrees of dissociation of the HSO₄ ^- ion, differential heats of dilution, heat capacities, freezing points, and tabulated partial molal enthalpies of water for aqueous H₂SO₄, from -1 at 1 atm pressure (1 atm = 101.325 kPa). The solution is treated as the mixture H⁺-HSO₄ ^--SO₄ ^2--H₂O. The equations yield a self-consistent representation of activities, speciation, and thermal properties which, for practical applications, is readily extended to more complex mixtures. Activity products of solutions saturated with respect to solid phases H₂SO₄·nH₂O (where n is 1, 2, 3, 4, or 6.5) are determined as functions of temperature. Thermodynamic properties and speciation are tabulated at 253.15, 273.15, 298.15, and 323.15 K.