What do you understand by dipole (polar) molecule ? Explain it by taking hydrogen chloride as an example.

A molecule that has both, slight positive and slight negative charge is called a dipole molecule.

For example - In hydrogen chloride, the strong nuclear charge of the chlorine atom (the electro-negativity of chlorine is 3) attracts the shared electron pair towards itself due to which a slight negative charge develops on the chlorine atom. The hydrogen atom (electronegativity 2.1) develops a slight positive charge. Therefore, a polar covalent bond is formed.