Why do different compounds have different solubilities?
There is a reason why oil and water do not mix — and why some compounds, like sugar, dissolve in water easily.
The answer lies in solubility — how easily one substance, a solute, dissolves in another substance — the solvent. When the solubility of a compound is discussed and the exact solvent is not mentioned, it usually means that the solvent is water.
A molecule’s solubility is determined by its degree of polarity. Not all molecules are polar, but for those that are, there is a partial negative charge on at least one part of the molecule and a partially positive charge on at least one other part.
Whether or not a molecule has these partial charges depends on electron distribution. Electrons, the near-weightless components of atoms that exist outside the atomic nucleus, are the bonding agents that form molecules. They hold atoms together to form molecules, and they are also negatively charged.
If the electrons are distributed evenly in a molecule, then the molecule is considered non-polar. This is the case with symmetrical molecules where no one atom has a comparatively larger pull on the electrons than others.
That said, some molecule contains one or more atoms that are particularly more electronegative, which makes electrons gravitate towards…
