Question:medium

Phenol on reaction with aqueous solution of bromine gives

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Phenol reacts with bromine water very easily because the \(-\text{OH}\) group strongly activates the ring. So bromination usually gives: \[ \text{2,4,6-tribromophenol} \] as the major product.
Updated On: May 14, 2026
  • o-Bromophenol
  • m-Bromophenol
  • p-Bromophenol
  • 2,4,6-tribromophenol
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The Correct Option is D

Solution and Explanation

Step 1: Understanding the Concept:
Phenol undergoes electrophilic aromatic substitution very easily because the \(-\text{OH}\) group is a highly activating, ortho/para directing group.
The lone pair on oxygen increases the electron density in the ring through resonance.
Step 2: Key Formula or Approach:
The approach involves identifying the effect of the solvent on the bromination of phenol.
In highly polar solvents like water (aqueous bromine), phenol ionizes to the phenoxide ion, which is even more reactive than phenol.
Step 3: Detailed Explanation:
When phenol reacts with bromine water (\(\text{Br}_2/\text{H}_2\text{O}\)), the reactivity is so high that substitution occurs at all available ortho and para positions simultaneously.
The phenoxide ion (\(\text{C}_6\text{H}_5\text{O}^-\)) formed in aqueous medium increases the ring's nucleophilicity significantly.
Consequently, multiple bromine atoms substitute the hydrogen atoms at positions 2, 4, and 6.
The reaction results in the formation of a white precipitate of 2,4,6-tribromophenol.
\[ \text{C}_6\text{H}_5\text{OH} + 3\text{Br}_2 \xrightarrow{\text{H}_2\text{O}} \text{C}_6\text{H}_2(\text{OH})(\text{Br})_3 + 3\text{HBr} \] Step 4: Final Answer:
Phenol reacts with aqueous bromine to give 2,4,6-tribromophenol.
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