Question

While separating a mixture of Para nitrophenol and ortho nitrophenol which one is steam volatile ?Give reason and draw the strctures.?

Answer 1

In Ortho nitrophenol , the nitro group forms an INTRAmolecular Hydrogen bonding with the hydroxyl group whereas in para nitrophenol, the nitro group participates in INTERmolecular hydrogen bonding with the hydroxyl groups of the other paranitrophenol molecules. Since intermolecular forces are much stronger than intermolecular forces , paranitrophenol boils at a much higher temperature than orthonitrophenol molecules. Hence orthonitrophenol is steam volatile.

Answer 2

Ortho Nitrophenol consist of intermolecular H-bonding and due to this the molecules of para nitrophenol are hardily allied. So, ortho nitrophenol will volatile.