Two intermolecular interactions of(1) hydrogen bond and (2) substitution effect were analyzed and compared, besides the investigation of intermolecular interactions between the two polar molecules forming the solution in a non polar solvent. For this purpose the FITR and 1H- NMR spectroscopic methods were used. The molecular acoustics provides information about the molecular behaviour of liquids owing to its ability of characterizing physico chemical behaviour of the medium. The results obtained allowed us to show that substitutents (NO2) in the para or the ortho position with respect to either OH or CHO in H-bonded systems which interact more strongly than the other systems. The substitutent effect, due to the intermolecular charge transfer from the ortho-counter substitutent (NO2) to the proton donating group (OH), is greater than for the interaction of para-OH with the proton-acceptor group (CHO).
