A model for excess volumes of salty water–acetonitrile mixtures at 298.15 K

A model for salty water–acetonitrile mixtures at 298.15 K was proposed based on three different contributions: chemical, physical and electrostatical. The first two were accomplished by ERAS model and the third was achieved by analyzing several proposals: Debye–Hückel, Hepler and a modified ERAS model. In order to test the model values, densities for the mixtures were measured with a vibrating-tube densimeter and the excess molar volumes were determined. The salts molar concentrations varied from 0.001 to 0.004, covering the entire composition range for water–acetonitrile. For each system, the three model approaches was applied. The modified ERAS model provides the best results.