Among ortho, meta and para substituted diahalobenzenes which has high melting point? Give reasonw ith example.

Among ortho, meta and para substituted diahalobenzenes which has high

1.	Among ortho, meta and para substituted diahalobenzenes which has high melting point? Give reasonw ith example.
Answer» Solution :The boiling POINTS of isomeric dihalobenzene are nearly the same. The melting point of para of para ISOMER is generally higher than the melting points of ortho and meta isomers. The higher melting point of p-isomer is due to its symmetry which leands to more close packing of its molecules in the crystal lattice and consequently strong INTERMOLECULAR attractive FORCE which requires more energy for melting. p-Dihalobenzene`GT`o-Dichlorobenzene`gt`m-Dichloro benzene.