Question

When phenol is treated with excess of bromine water, it gives

• A. o-bromophenol
• B. o- and p-bromophenol
• C. 1,3,5-tribromophenol
• D. 2,4-dibromophenol
• E. 2,4,6-tribromophenol

Hint:

Chemistry Tip: Phenol + bromine water is a classic test giving white ppt of 2,4,6-tribromophenol.

Answer 1

Answer: (E)

Concept:
Phenol contains the group: $$-OH$$ The lone pair on oxygen strongly activates benzene ring and directs substitution to:

• ortho positions (2,6)
• para position (4)

Thus phenol undergoes bromination easily even without catalyst.
Step 1: Why rapid bromination occurs.
Resonance donation from oxygen increases electron density in ring: $$\text{Phenol} \rightarrow \text{activated aromatic ring}$$ Hence bromine water reacts quickly.
Step 2: Effect of excess bromine water.
Since ring is highly activated, substitution occurs at all activated positions:

• 2-position
• 4-position
• 6-position

Thus product formed is: $$2,4,6\text{-tribromophenol}$$
Step 3: Observation.
Reaction gives:

• Decolourisation of bromine water
• White precipitate of tribromophenol

Step 4: Reaction equation.
$$C_6H_5OH + 3Br_2 \rightarrow C_6H_2Br_3OH + 3HBr$$
Step 5: Final answer.
Hence product is: $$\boxed{2,4,6\text{-tribromophenol}}$$ Therefore correct option is: $$\boxed{\text{(E)}}$$ :contentReference[oaicite:1]{index=1}