Question

I have a doubt about solubility: a molecule is polar when it has a dipole moment that is ≠ 0. Very often it is said that like dissolves like, that is, that polar substances dissolve in polar solvents, and apolar substances dissolve in apolar solvents. But this is not always true: for example, 1 - hexanol is polar (its dipole moment is ≠ 0), but it is not soluble in water. This means that polarity does not imply water solubility. That said, what do you rely on to roughly predict solubility?

Answer 1

Solubility can be roughly predicted by considering 'like dissolves like' and focusing on intermolecular interactions such as hydrogen bonding and dipole-dipole interactions. Substances will generally dissolve if the intermolecular forces match those of the solvent.

Step-by-step explanation:

To roughly predict solubility, you can often rely on the principle of 'like dissolves like'. However, this is not a fail-proof rule, and there are exceptions. One must consider the intermolecular interactions, such as hydrogen bonding, dipole-dipole interactions, and London dispersion forces. For instance, though 1-hexanol is polar, it has a long nonpolar chain that hinders its solubility in water. Generally, if the intermolecular forces of the solvent are similar to those of the solute, the greater the likelihood of solubility. Hydrophilic substances, which are water-loving, dissolve in water, while hydrophobic substances, which fear water, do not.