p-Dichlorobenzene has higher m.p. and solubility than those of -and m-isomers. Discuss.

Explanation

The p-isomer being more symmetrical fits closely in the crystal lattice and thus has stornger intermolecular forces of attraction than those of o- and m-isomers. Since during melting or dissolution, the crystal lattice breaks, therfore, a larger amount of energy is needed to melt or dissolve the p-isomer than the corresponding o-and m-isomers. in other words, the melting point of the p-isomer is higher and it ssolubility lower than the corresponding o- and -isomers.