Question

explain why o nitrophenol has more boiling point than p nitrophenol

Answer 1

o-nitrophenol forms intramolecular H bond and no association occurs whereas molecules of p-nitrophenol get associated through intermolecular H bonding and boils relatively at higher tem. (above the B.P.of water). Hence,only

ortho-nitrophenol is steam volatile.


                    or
Ortho nitophenol shows intramolecular hydrogen bonding, Whereas para nitro phenol shows inter moleculr hydrogen bonding.
In intermolecular hydrogen bonding association of molecules take place, but in intramolecular hydrogen bonding there is no such type of association between the molecules. Due to this reason para nitrophenol has higher boiling point than ortho nitro phenol.

Answer 2

due to more inductive effect at ortho position
and also due to hydrogen bonding