Partial molal Volumes of tetraalkylammonium chlorides in ethanol–water mixtures

The partial molal volumes of four tetraalkylammonium chlorides, Me4NCl, Et4NCl, Pr4NCl, and Bu4NCl, in a series of ethanol–water mixtures have been determined. The experimental results are discussed in terms of the varying size and surface charge of the ions and the structure of the binary solvent mixtures. The results indicate that at 0.1 mole fraction ethanol the maximum structuredness of water causes a minimum in the partial molal volumes, while at 0.3 mole fraction the solvent structure is such that the free volume is a minimum but the effect of surface charge on the salts is a maximum.