Question

Why is common salt insoluble in ethyl alcohol?

Answer 1

Because ethyl (and higher) alcohols are incapable of solvating `Na^+` and `Cl^-` ions.

Explanation:

Sodium chloride, and other ionic solids, have some solubility in aqueous solvents:

`NaCl(s) rightleftharpoons Na^(+)(aq) + Cl^(-)(aq)`

We write `Na^(+)(aq)`. What we mean by this is the aquated ion `[Na(OH_2)_6]^+`, which is, if you like, a coordination complex of sodium ion with water ligands, i.e. hexaquasodium cation. In ethanol, this sort of solvent ion complex is not supported.