Evaluate the following statements regarding the dipole moments of halogenated aromatic compounds. Wh — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

A) True. In $p$ -dichlorobenzene, the two $C-Cl$ bonds are at a $180^\circ$ angle, making the resultant vector sum exactly zero. B) True. An $sp^2$ hybridized carbon has more $s$ -character ($33\%$) and is more electronegative than an $sp^3$ carbon ($25\%$). This reduces the electronegativity difference between C and Cl in chlorobenzene compared to cyclohexyl chloride, lowering the dipole moment. C) False. $o$ -Dichlorobenzene ($60^\circ$ angle) has a higher resultant dipole moment ($\approx \sqrt{3}\mu$) than $m$ -dichlorobenzene ($120^\circ$ angle, $\approx \mu$). D) True. The $-I$ effect pulls electron density towards Cl, while the $+R$ effect pushes lone pair electron density back towards the ring. These opposing vectors partially cancel, resulting in a lower net dipole moment.