Question

Write the significance/applications of dipole moment.

Answer 1

The separation of charges in a system produces dipole moment. Ionic and covalent compounds develop dipole moments. The dipole moment is produced due to the difference in electronegativity of the chemically bonded atoms.

Complete answer:
The separation of positive and negative charges in a compound is known as polar character. The measurement of polar character of a chemical bond is given by the dipole moment. The dipole moment has both magnitude and direction and thus, it is a vector quantity.
The positive charge is indicated by $\delta+$ and the negative charge is indicated by $\delta-$. These charges are separated by distance ${\text{d}}$ and are equal in magnitude but opposite in direction.
The significance/applications of dipole moment are as follows:

Dipole moment is useful in finding the polar nature of the chemical bond: As the magnitude of dipole moment increases, the polar nature of the bond increases. Molecules with zero dipole moment are non-polar in nature. Molecules having dipole moments are said to be polar.
Dipole moment is useful in finding the structure/shape of the molecule: Molecules having dipole moment are bent or angular in shape and have unsymmetrical structure. Molecules having zero dipole moment have symmetrical shape.
Dipole moment is useful in distinguishing between the cis- and trans- isomers: Isomers having high dipole moment are trans-isomers. Isomers having low dipole moment are cis-isomers.
Dipole moment is useful in distinguishing between the ortho, meta and para- isomers: The isomer having zero dipole moment is the para-isomer. The isomer having moderate dipole moment is the meta-isomer. The isomer having the highest dipole moment is the ortho-isomer.
Dipole moment is useful in finding the percent ionic character.

Note: Dipole moment is the product of magnitude of charge and the internuclear distance. The formula to calculate the dipole moment is,
$\mu = Q \times d$
Where $\mu$ is the dipole moment,
Q is the magnitude of the charge,
d is the internuclear distance