Estimating the number of water molecules squeezed out of the surface layer at the air-solution interface during adsorption of a surface-active substance molecule

The thermodynamic equation of Bockris is used to calculate the number v(H2O) of water molecules that are squeezed out of the surface layer at the air-solution interface during adsorption of a single molecule of a surface-active substance. It is shown that v(H2O) depends on the dipole moment of the polar group and their number in an organic molecule. For benzene, v(H2O) approximate to 0; for phenol, aniline, benzyl alcohol, aliphatic alcohols,and acids with a rather long carbon chain, v(H2O) approximate to 3; while for hydroquinone and pyrogallol, v(H2O) = 4 to 5.