ABSTRACT
The presence of lone-pair electrons confers electrical asymmetry on electrically neutral molecules. A given kind of molecule will be water soluble if that molecule's electrical asymmetry is complementary to the electrical asymmetry of water, thus providing a relatively stable interaction. Water is therefore "soluble in itself". Sodium chloride is highly soluble in water. The stabilizing attraction between the sodium ion and the oxygen lone pair, and that between the chlorine ion and the hydrogen of water, are electrostatically a bit similar to hydrogen bonds. The interaction between water and an ion is a dipole-monopole interaction. Water is so strongly attracted to the sodium and chloride ions that those ions can seldom reassociate with each other in solution. At a hydrocarbon-water interface a water molecule cannot form four hydrogen bonds to other water molecules because half of what each water molecule "sees" at the user interface is hydrocarbon.
