Name: Hybridisation in SF₆ Molecule
Uploaded: 2019-07-19
Duration: 2 min 31 s
Description: Understand the bonding present in the case of sulphur hexafluoride. This video illustrates that the hybridisation present in the case of sulphur hexafluoride...

Question

Define dipole moment. Write its applications.

Accepted Answer

Dipole moment is the measure of degree of polarity of a bond, and is defined as the product of the magnitude of the charge and the distance between the centres of positive and negative charges. It is usually represented by a Greek letter $μ$ (mu). Mathematically, it is expressed as:
"Dipole moment "( $μ$ ) $=$ Charge ( $Q$ ) $\times$ Distance of separation ( $r$ ). It is generally expressed in Debye units ( $D$ ).

Applications of dipole moment are given below:

(i) Dipole moment is useful in calculating the percent ionic character of polar covalent bonds:
$%$ ionic character $= \frac{μ_{0 bserved}}{μ_{calculated}} \times 100$ .

(ii) Dipole moment is useful in predicting the shapes of molecules:
a) In the case of ${AX}_{2}$ type molecules, if dipole moment is zero they have linear structure but if they have some dipole moment values, they are angular.
b) ${AX}_{3}$ type molecules with dipole moment zero are planar triangular but, if they have some dipole moment values, they have pyramidal shape.
c) ${AX}_{4}$ type molecules with dipole moment zero have symmetric tetrahedral structure but, if they have some dipole moment values, they have distorted tetrahedral shape.
d) In geometrical isomers, trans-isomers have zero dipole moment while, cis-isomers have some dipole moment values.

(iii) It is useful to predict the polarity of molecule: The molecules with dipole moment greater than zero are polar, and the molecules with dipole moment equal to zero are non-polar.

Define dipole moment. Write its applications.

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