Dipole moment of a bond is a vector and physical quantity to calculate the parentage ionic character in a covalent bond. It is expressed as:

Dipole moment $\left(\mu \right)=\overrightarrow{\delta }\times d$
where $\delta$ is dipole moment and d is the bond length. It is usually expressed in terms of CGS unit known as Debye

(D). $1\mathrm{D}={10}^{-18}$ esu $\mathrm{cm}.$ In SI unit it is expressed in Coulomb meter. Resultant moment $\left({\mu }_R\right)$ of two bond moments $\left({\mu }_1\text{ and }{\mu }_2\right)$ acting at an angle $\theta$, is given by

${\mu }_R=\sqrt{{\mu }_1^2+{\mu }_2^2+2{\mu }_1{\mu }_2\cos \theta }$

If ${\mu }_1={\mu }_2,$ also if $\cos \theta =-1,$ i.e., $,\theta =180°,$ then $\mu =0$

(molecule is non-polar).

If $\mu \equiv 0$ molecule is polar. Dipole moment plays an important role in deciding the stability order of alkanes, i.e., a more stable alkane has less dipole moment. The dipole moment of a molecule can predict the geometrical and position isomers as well as orientations in benzene nucleus and polarity of molecule.

The increasing order of dipole moment of bond in halogen acids is

Dipole moment of a bond is a vector and physical quantity to calculate the parentage ionic character in a covalent bond. It is expressed as:

Dipole moment 
where  is dipole moment and d is the bond length. It is usually expressed in terms of CGS unit known as Debye

(D).  esu  In SI unit it is expressed in Coulomb meter. Resultant moment  of two bond moments  acting at an angle , is given by

If  also if  i.e.,  then 

(molecule is non-polar).

If  molecule is polar. Dipole moment plays an important role in deciding the stability order of alkanes, i.e., a more stable alkane has less dipole moment. The dipole moment of a molecule can predict the geometrical and position isomers as well as orientations in benzene nucleus and polarity of molecule.

Which molecule is non-polar?

Dipole moment of a bond is a vector and physical quantity to calculate the parentage ionic character in a covalent bond. It is expressed as:

Dipole moment 
where  is dipole moment and d is the bond length. It is usually expressed in terms of CGS unit known as Debye

(D).  esu  In SI unit it is expressed in Coulomb meter. Resultant moment  of two bond moments  acting at an angle , is given by

If  also if  i.e.,  then 

(molecule is non-polar).

If  molecule is polar. Dipole moment plays an important role in deciding the stability order of alkanes, i.e., a more stable alkane has less dipole moment. The dipole moment of a molecule can predict the geometrical and position isomers as well as orientations in benzene nucleus and polarity of molecule.

Which species is polar?