question_answer 27)

P-Dichlorobenzene has higher melting point and tower solubility than those of o-and m-isomers. Discuss. Symmetry of the molecule is related to its crystal lattice structures and hence, to ifs melting point and solubility. A highly symmetrical structure has a higher melting point.  

Answer:

Sol.                               Out of the above three isomers of dichlorobenzene, the p-isomer ismore symmetrical than other two isomers. So, it has more closelypacked arrangement of molecules in its crystal lattice. So,p-dichlorobenzene has a higher melting point and lower solubility ascompared to ortho and meta isomers.