Heats Of Mixing Aqueous Electrolytes. XII. Reciprocal Salt Pair Na+, Li+.dvr.Cl-, SO42-
Journal Of Physical Chemistry
The heats of mixing aqueous solutions of all combinations of the reciprocal salt pair Na⁺, Li⁺ || Cl⁻, SO₄²⁻ have been measured at 25°. In one set of experiments, the initial solutions had the same molal ionic strength (I = 1, 3, or 6 mol/kg). In another set of experiments, the initial solutions had the same number of equivalents per kilogram of solvent (E = 1, 3, or 6 mol/kg). For charge-asymmetric mixtures, the magnitude of constant E mixings is about the same as that of the constant I mixings. Young's cross-square rule is quite accurate at I = 3 mol/kg and E = 3 and 6 mol/kg, marginal at I and E = 1 and fails definitely at I = 6 mol/kg. The constant E mixing process is preferred because the cross-square rule holds at higher concentrations. The predictions of the cross-square rule based on both constant I and constant E mixings are surprisingly accurate at these high concentrations in view of the fact that sodium and sulfate as well as lithium and sulfate ions have rather strong interactions.
R. H. Wood, D. E. Smith, H. K. W. Chen, and Peter T. Thompson.
"Heats Of Mixing Aqueous Electrolytes. XII. Reciprocal Salt Pair Na+, Li+.dvr.Cl-, SO42-".
Journal Of Physical Chemistry.