What determines the solubility of a molecule in water?

Factors effecting the solubility of a molecule in water;

a) Polarity:

As water is a polar solvent therefore, the molecule to be dissolved in it should be polar in nature as "Like dissolves Like". Polar means having a partial positive end and partial negative end. As in water oxygen has partail negative charge and hydrogen atoms has partial positive charges so, the molecule must contain these two charges. Therefore, it will develop intermolecular interactions and will dissolve it in water.

b) Temperature:

Solubility of substance increases with increasing temperature. Hence, by increasing temperature the solubility of polar molecule can increase in water.

c) Surface Area:

Greater the surface area greater is the solubility of solute in solvent because it will provide more surface to water solvent to interact with the solute.