Question

How dipole moment explain the polarity of a molecule

Answer 1

Dipole moments occur when there is a separation of charge.
Dipole moment arise from differences in electronegativity. As difference in electronegativity increases,polarity increases.

The larger the difference in electronegativity, the larger will be the dipole moment.

So larger the dipole moment, larger will be the polarity of molecule.Thus dipole moment explains the polarity of molecule.