Question

Identify the major product formed when phenol reacts with bromine water.

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

Hint:

Phenol reacts very rapidly with bromine water without a catalyst and forms 2,4,6-tribromophenol as a white precipitate.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question explores the reactivity of phenol in an aqueous medium during a halogenation reaction.
Step 2: Key Formula or Approach:
Phenol is highly activated toward electrophilic substitution because of the \( +M \) effect of the \( -OH \) group. Water, being a polar solvent, further ionizes phenol into a phenoxide ion, which is even more reactive.
Step 3: Detailed Explanation:
When bromine water (\( Br_2/H_2O \)) is added to phenol, the high reactivity leads to multiple substitutions.
Bromine atoms substitute the hydrogen atoms at both ortho positions (2 and 6) and the para position (4) simultaneously.
The reaction is:
\[ C_6H_5OH + 3Br_2 \xrightarrow{H_2O} C_6H_2(Br)_3OH + 3HBr \]
The product, 2,4,6-tribromophenol, is observed as a white precipitate.
Step 4: Final Answer:
The major product is 2,4,6-tribromophenol.