Question

Arrange the following compounds in order of increasing dipole moment, toluene (I), m-dichlorobenzene (II), o-dichlorobenzene (III),p-dichlorobenzene (IV)

• 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

Answer 2

p-dichlorobenzene is non-polar.
The two dipole vectors cancelling each other giving zero
resultant dipole moment, o-dichlorobenzcne has greater
dipole moment than meta isomer.
Toluene is less polar than both ortho and para
dichlorobenzene. Therefore, the increasing order of dipole
moment is
p-dichlorobenzene < toluene < m-dichlorobenzene
< o-dichlorobenzene