Question

Why para isomers have large melting and boiling point?

Answer 1

Generally, the melting point of para isomer is quite higher than that of ortho or meta isomers. This is due to the fact that it has a symmetrical structure and therefore, its molecules can easily pack closely in the crystal lattice. As a result, intermolecular forces of attraction are stronger and therefore, greater energy is required to break its lattice and its melts at higher temperature. 

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