Question

Arrange the following compounds in order of increasing dipole moment.
(i) toluene
(ii) m-dichloro benzene
(iii) o-dichloro benzene
(iv) p-dichloro benzene

• A. (i) $<$ (iv) $<$ (ii) $<$ (iii)
• B. (iv) $<$ (i) $<$ (ii) $<$ (iii)
• C. (iv) $<$ (i) $<$ (iii) $<$ (ii)
• D. (iv) $<$ (ii) $<$ (i) $<$ (iii)

Answer 1

Answer: (B)

(iv) $<$ (i) $<$ (ii) $<$ (iii)

The dipole moments of m-dichloro benzene, o-dichloro benzene and p-dichloro benzene is shown above and the dipole moment of toluene is less than them-dichloro benzene and o-dichloro benzene due to lesser electronegativity of -methyl group.
Hence the correct order is -
$\left(iv\right)<\left(i\right)<\left(ii\right)<\left(iii\right)$
Option B is correct.