Explain the polar covalent bond with the help of a suitable example.

(N/A) When two dissimilar atoms having different electronegativities combine to form a covalent bond,the bond pair of electrons is not shared equally.
The bond pair shifts towards the nucleus of the atom having greater electronegativity. As a result,the electron distribution becomes distorted and the electron cloud is displaced towards the more electronegative atom.
Consequently,the electronegative atom acquires a partial negative charge $(\delta^-)$,while the other atom acquires a partial positive charge $(\delta^+)$. Thus,opposite poles are developed in the molecule,and this type of bond is called a polar covalent bond.
Example: $HCl$ contains a polar covalent bond. The chlorine atom is more electronegative than the hydrogen atom. Hence,the bond pair lies closer to the chlorine atom,which acquires a partial negative charge,while the hydrogen atom acquires a partial positive charge: $H^{\delta+} - Cl^{\delta-}$.