Question

What is the major product formed when phenol reacts with bromine water?

• A. Bromobenzene
• B. 2-bromophenol
• C. 2,4-dibromophenol
• D. 2,4,6-tribromophenol

Hint:

Phenol is highly activating toward electrophilic substitution. With bromine water, it undergoes rapid substitution at the ortho and para positions, producing \(2,4,6\)-tribromophenol as a white precipitate.

Answer 1

The Correct Option is D

Concept: Phenol contains a highly activating \( -OH \) group which increases the electron density on the benzene ring. This strongly activates the ortho and para positions for electrophilic substitution reactions.

Step 1: Understand the reactivity of phenol.
The hydroxyl group donates electron density to the aromatic ring through resonance, making the ring highly reactive toward electrophiles.

Step 2: Reaction with bromine water.
When phenol reacts with bromine water, bromination occurs rapidly at the two ortho positions and the para position relative to the \( -OH \) group.

Step 3: Formation of the product.
Thus, three bromine atoms substitute hydrogen atoms at positions 2, 4, and 6 of the benzene ring, forming: \[ \text{2,4,6-tribromophenol} \] This compound appears as a white precipitate in the reaction mixture.