Question

Why boiling point of meta dichlorobenzene is less than para?

Answer 1

Due to symmetrical structure of para-dichloro benzene there exist strong intermolecular forces than in ortho and meta- isomers of dichloro benzene. It requires high energy for p-dichloro benzene than o- & m- dichloro benzene to break these bonds during dissolution and boiling. Therefore p-dichlorobenzene has higher boiling point and lower solubility than ortho and meta dichlorobenzene