Partial Molar Volumes in Aqueous Mixtures of Nonelectrolytes. IV. Aromatic Hydrocarbons

Abstract

Abstract The densities of binary mixtures of water with benzene, toluene, and ethylbenzene were measured for both ends of the concentration range at 5, 15, 25, 35, and 45 °C. The partial molar volumes were evaluated for both components by assuming a linear correlation of the density with the concentration. The partial molar volumes of the aromatic hydrocarbons (VA) in a water-rich region are smaller than the molar volumes of the respective solutes, but the temperature dependences of the VA are almost the same as the molar expansibilities of the solutes. On the other hand, the partial molar volumes of water (VW) and their temperature dependences in a hydrocarbon-rich region are appreciably larger compared with the molar volume and molar expansibility of pure water, respectively. The results are discussed on the basis of the scaled particle theory and interpreted in terms of the difference of the compressibilities of the solvents. The volumetric behavior of the aromatic hydrocarbons in aqueous solutions does not bear out any influence of a so-called iceberg structure.