A model of a liquid surface in which there is no negative or positive surface Concetration would have the solute uniformly distributed right out to the surface.
In electrolye solutions an ion tends to be surrounded by ions of the opposite charge, but at the sdrface there are ions that are not uniformly surrounded. There is, therefore, an unbalanced electrostatic force tending to draw these surface ions into the body of the solution.
In Fig a a more nearly correct modelis shown, in which the ions bave largely drawn away from