Question

Arrange the following compounds in order of increasing dipole moments:
I. Chlorobenzene
II. m-dichlorobenzene
III. o-dichlorobenzene
IV. p-dichlorobenzene

• A. $I>IV>II<III$
• B. $IV<I=II<III$
• C. $IV<I<III>II$
• D. $IV>II<III>I$

Answer 1

The correct option is B $IV<I=II<III$

The dipole moment of p-dichlorobenzene is zero. Chlorobenzene and m-dichlorobenzene have the same dipole moment.
Again, o-dichlorobenzene has a higher dipole moment than m-dichlorobenzene due to lower angle. Hence, the order becomes: $IV<I=II<III$