The apparent molal volumes of mixtures of 1:1 electrolytes in aqueous urea solutions: A test of Young's rule

The apparent molal volumes of sodium chloride, sodium bromide, potassium chloride, and potassium bromide were determined for each salt at 2.000m in 8.000m urea-in-water solvent systems at 25°C. In each instance, the volumes were larger than those observed for the same salts in pure water. The volume changes on mixing the six pairs of these salts were measured at a constant ionic strength of 2m in the same urea-water solvent. The results of this test suggest that Young's rule applies equally well in urea-water solvent systems as it does in pure water.