The properties of the methanol/ethanol/acetone ternary mixture can be accurately described in terms of its-acidity, basicity, and dipolarity/polarizability, which can be readily evaluated by using suitable probe/homomorph couples. These mixtures form acetone/alcohol complexes that increase their polarity with respect to the pure components. Contrary to the assumptions of the preferential solvation model, the composition of the bulk mixture needs not be different from that around a solute. (C) 2003 Elsevier Science B.V. All rights reserved.