Question

Reaction of phenol with which of the following reagents form picric acid?

• A. Conc. $ \text{H}_2\text{SO}_4 $
• B. dil. $ \text{H}_2\text{SO}_4 $
• C. Conc. $ \text{HNO}_3 $
• D. dil. $ \text{HNO}_3 $

Hint:

Concentrated nitric acid is needed for the exhaustive nitration of phenol to form picric acid.

Answer 1

The Correct Option is C

Step 1: Understand the structure of phenol and picric acid.

Picric acid is 2,4,6-trinitrophenol.

Step 2: Recall the nitration of phenol.

Phenol is activated towards electrophilic substitution.

Step 3: Consider the reagents.

Conc. HNO₃ is a strong nitrating agent.

Dil. HNO₃ leads to mono-nitration.

H₂SO₄ leads to sulfonation.

Step 4: Identify the correct reagent for picric acid formation.

Concentrated HNO₃ nitrates phenol at the 2, 4, and 6 positions.

Step 5: Conclusion.

Conc. HNO₃ reacts with phenol to form picric acid.