The Shannon information entropies in position and momentum space of H2O, HCN, HOOH, NH3, CH2O2, CH3NH2, CH3OH, CH3CHO, CH3OCH3, CH3COCH3, NH2OH, NH2COH, and CH3NHCOH at the RHF/6-31++G** level in vacuo and in the Onsager aqueous field, were calculated and correlated with various properties. The local entropy of atoms and functional groups in these molecules were also investigated. The results show that the response of the electron density of the groups to solvation is such as to minimize electron transfer to or from the group, and its associated entropy change, which implies a stability of the functional groups within the molecular framework. The effect of solvent fields with increasing dielectric constant on the Shannon entropy of water was studied. The relationships between position and momentum densities through the Shannon entropy are discussed.