Question

Ortho-Nitrophenol is more volatile than $p$-nitrophenol because of :

• A. resonance in the molecule.
• B. hyperconjugation
• C. presence of intermolecular hydrogen bonding in the ortho-isomer.
• D. presence of intramolecular hydrogen bonding in the ortho-isomer.

Answer 1

The correct option is D presence of intramolecular hydrogen bonding in the ortho-isomer.

Ortho-nitrophenol has intramolecular hydrogen bonding whereas p-nitrophenol has intermolecular hydrogen bonding which is very strong. As a result Orhtonitrophenol has lower boiling point than paranitrophenol.

For eg. if we are heating both the compounds Orthonitrophenol react faster due to the lower boiling point than Paranitrophenol. SO orthonitrophenol is considered to be steam volatile.

Hence opt. D is correct.