Question

Explain dipole (polar) molecule by taking hydrogen chloride as an example.

Answer 1

In hydrogen chloride, the chlorine atom's strong nuclear charge (3 electro-negativity) attracts the shared electron pair, resulting in a slight negative charge (δ⁻) on the atom. The hydrogen atom (electronegativity 2.1) generates a little positive charge (δ⁺). Thus, a polar covalent link is produced. This is shown below.

\[\ce{\underset{H-atom}{H^×} + \underset{Cl-atom}{_{\bullet}\overset{\bullet\bullet}{\underset{\bullet\bullet}{Cl}^{\bullet}_{\bullet}}}->    H^{×}_{\bullet}\overset{\bullet\bullet}{\underset{\bullet\bullet}{Cl}^{\bullet}_{\bullet}}->H^δ+ -> Cl^δ−}\]