Arrange the following in order of increasing dipole moment (I) Toluene (II) m-dichlorobenzene (III) $o-$dichlorobenzene (IV) $p-$dichlorobenzene :

IV < I < III < II

$p-$dichlorobenzene has zero dipole moment because of the symmetrical structure.

o-dichlorobenzene has more dipole moment than its meta isomer because of having low bond angle.