Question

Arrange in order of increasing dipole movement.

I. Toulene

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. $IV<II<I<III$

Answer 1

The correct option is B

$IV<I<II<III$

$C{H}_3$ of toluene is electron donating.

In p-dichlorobenze, the dipole moments by each $Cl$ cancel out and thus no net dipole moment exists. Among m and o isomers, Ortho isomer has more net dipole moment.

Toulene has a $e^{-}$ donating $-C{H}_3$ group which is weaker than chlorine

So, the order will be:-

$IV<I<II<III$