he intramolecular hydrogen bonding is present in:

• A. o-nitrophenol
• B. m-nitrophenol
• C. p-nitrophenol
• D. Phenol

The presence of intramolecular hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom, such as oxygen, within the same molecule. In the case of the options provided:

Options Analysis

• o-Nitrophenol: This compound can form intramolecular hydrogen bonds due to the proximity of the hydroxyl group and the nitro group.
• m-Nitrophenol: The arrangement of the groups does not favor intramolecular hydrogen bonding.
• p-Nitrophenol: Similar to m-nitrophenol, the structure does not allow for intramolecular bonding.
• Phenol: This compound lacks a nitro group, so intramolecular hydrogen bonding is not applicable.

Conclusion

Among the given options, o-nitrophenol is the only compound that exhibits intramolecular hydrogen bonding due to its structural arrangement.