Hydrophilic Repulsion

Repulsion between two solute particles means leads to greater solubility of the solute. On the other hand, attraction between two solute particles would lead to phase separation and result in lesser solubility.

Solubility of Solute (1) in water

Here is the contactable surface are between the molecules,

is the Boltzmann constant,

is the solubility , and

is the temperature

A higher means higher solubility. And if then the solute has a low solubility.

Thus, for solutes which are highly soluble in water, the interfacial tension is negative.

At

(4.9)