Among ortho, meta and para substituted diahalobezenes which has high melting point ? Give reason with example.

Among ortho, meta and para substituted diahalobezenes which has high m

1.	Among ortho, meta and para substituted diahalobezenes which has high melting point ? Give reason with example.
Answer» Solution :The boiling POINTS of isomeric dihalobenzene are nearly the same . The MELTING POINT of para issomer is generally higher than the melting point of ortho and meta isomers. The higher melting point of p-isomer is due to its symmetry which leads to more close PACKING of its moleculars in the crystal lattice and consequently strong intermolecular attractive force which REQUIRES more energy for melting. p-Dihalobenzene`gt` o-Dichlorobenzene ` gt` m-Dichlorobenzene.