Question

It is possible to separate o-nitrophenol and p-nitrophenol using steam distillation because o-nitrophenol has

• A. Van der Waals force
• B. Steric hindrance
• C. Intermolecular H-bonding
• D. Intramolecular H-bonding

Hint:

In steam distillation, intermolecular hydrogen bonding in a compound affects its volatility and can play a key role in separation from compounds with weaker intermolecular forces.

Answer 1

The Correct Option is C

Step 1: Understanding the behavior of o-nitrophenol.
O-nitrophenol (ortho-nitrophenol) exhibits intermolecular hydrogen bonding between the hydrogen of the hydroxyl group and the oxygen of the nitro group in the ortho position. This intermolecular hydrogen bonding increases the boiling point of o-nitrophenol compared to p-nitrophenol, which does not have this type of hydrogen bonding.
Step 2: Effect of intermolecular H-bonding.
Intermolecular hydrogen bonding in o-nitrophenol reduces its volatility under normal conditions. However, during steam distillation, o-nitrophenol can still be separated due to the relatively weaker intermolecular forces compared to p-nitrophenol, which lacks such bonding.
Step 3: Conclusion.
Thus, o-nitrophenol can be separated from p-nitrophenol via steam distillation due to the presence of intermolecular hydrogen bonding in o-nitrophenol.