Question

Name the products formed when phenol is treated with the following reagents: 
(i) Bromine water 
(ii) Zinc dust 
(iii) Conc. HNO_3 

• A.
• B.
• C.
• D.

Hint:

Important Reactions of Phenol: Bromine water → 2,4,6-Tribromophenol (white precipitate) Zinc dust → Benzene Conc. $HNO_3$ → 2,4,6-Trinitrophenol (Picric acid) The –OH group activates the benzene ring and directs substitution mainly to ortho and para positions.

Answer 1

The Correct Option is A

Concept:
Phenol is highly reactive towards electrophilic substitution reactions because the hydroxyl group activates the benzene ring and directs incoming groups to the ortho and para positions.

Step 1: Reaction with Bromine Water.
Phenol reacts readily with bromine water at room temperature to form a white precipitate of 2,4,6-tribromophenol.

C6H5OH + 3Br2 → C6H2Br3OH + 3HBr

Thus, the product formed is 2,4,6-tribromophenol.

Step 2: Reaction with Zinc Dust.
When phenol is heated with zinc dust, the oxygen atom is removed and phenol is reduced to benzene.

C6H5OH + Zn → C6H6 + ZnO

Hence, the product formed is benzene.

Step 3: Reaction with Concentrated Nitric Acid.
Phenol undergoes nitration with concentrated nitric acid to form 2,4,6-trinitrophenol, commonly known as picric acid.

C6H5OH + 3HNO3 → C6H2(NO2)3OH + 3H2O

Thus, the product obtained is 2,4,6-trinitrophenol (picric acid).