Question

$o$-nitrophenol is more volatile than $p$-nitrophenol because of:

• A. Steric hindrance
• B. Hyperconjugation
• C. Intra-molecular H-bonding
• D. Resonance

Answer 1

The correct option is C Intra-molecular H-bonding

In the case of o-nitrophenol, intramolecular hydrogen bonding is present.
Intra molecular H-bonding in o-nitrophenol involves only single molecule, thus low B.P and high volatile nature.

In the case of p - nitrophenol, intermolecular hydrogen bonding is present due to which molecules are accomodated closer. Hence, it is less volatile than o-nitrophenol.



When both the compounds are boiled, the strong intermolecular hydrogen bonding increases the boiling point. Therefore o-nitrophenol has less boiling point and is more steam volatile than p-nitrophenol.