Thermodynamic functions of solvation in mixtures of water with acetone and acetonitrile are measured at T = 298.15 K.

Solvation of n-octane and toluene in aqueous-organic mixtures is studied.

When increasing water content, Gibbs free energies grow up steadily, while enthalpies have a maximum.

Hydrocarbons are preferentially solvated with organic cosolvent even in mixtures with rather high water content.

Acetonitrile suppresses the hydrophobic effect less than acetone.