Explain with the help of suitable example polar covalent bond.
In a heteronuclear molecule, the shared electron pair between the two atoms gets displaced more towards the atom with higher electronegativity. The resultant covalent bond is called a polar covalent bond.
A suitable example is the hydrogen fluoride (HF) molecule. In HF, the shared electron pair gets displaced more towards fluorine since the electronegativity of fluorine is far greater than that of hydrogen.
As a result of this polarisation, the molecule possesses a dipole moment (). It is defined as the product of the magnitude of the charge and the distance between the centres of positive and negative charge.
Explanation
The answer explains polar covalent bonds using the HF example directly from the textbook context. It highlights how differences in electronegativity between heteronuclear atoms cause the shared electron pair to shift, leading to polarisation and the creation of a dipole moment.