In this work we conduct a systematic ab initio study of the solvation of small alkane, monoalcohol and diol molecules, in polar solvents with different properties. A choice of basis set suitable for the type of compounds under study is presented. The various components of the solvent–solute interaction and the cavitation energy are treated individually and their variation with chain length and introduction of hydroxy groups assessed. The use of solute molecules in which controlled changes are imposed allows for an estimation of the relative contributions, thus eliminating accidental error cancellation.Fundacão para a Ciência e Tecnologia SAPIENS POCTI/35415/QUI/200