(a) Significance of dipole moment :-
Dipole moment (M) = charge (Q) × distance of separation (r)
Dipole moment is usually expressed in Debye 'units. (D).
(i) It helps to per predict polar and non-potar nature of compounds.
(ii) The percentage of ionic character can be calculated.

$\% \mathrm{of} \mathrm{ionic} \mathrm{character}=\frac{\mathrm{Mobserved}}{\mathrm{Meafeulated}}\times 100$

(iii) It helps to know the symmetry of molecule. symmetrical molecules have zero dipole moment, although they have two or mare polar bonds.
(b) The diagrams and net dipole moments are shown in the figures above :