Question

Identify the product when Phenol reacts with Bromine water.

• A. \(o\)-Bromophenol
• B. \(m\)-Bromophenol
• C. \(2,4,6\text{-Tribromophenol}\)
• D. Bromobenzene

Hint:

Phenol reacts very rapidly with bromine water because the \(-OH\) group strongly activates the benzene ring. Unlike benzene, this reaction does not require a Lewis acid catalyst such as \(FeBr_3\). The reaction directly forms \(2,4,6\)-tribromophenol with a characteristic white precipitate.

Answer 1

The Correct Option is C

Concept:
Phenol undergoes Electrophilic Aromatic Substitution. The hydroxyl (\(-OH\)) group is a highly activating, ortho/para-directing group because it increases electron density on the ring through resonance.
Step 1: Understanding the Question:
We need to determine what happens when phenol is treated with bromine water (\(Br_2/H_2O\)). Bromine water is a polar medium which facilitates the ionization of phenol into the phenoxide ion, making the ring extremely reactive.
Step 2: Key Formula or Approach:
Identify the directing effect of the \(-OH\) group. In polar solvents like water, phenol is so reactive that substitution occurs at all available ortho (\(2,6\)) and para (\(4\)) positions simultaneously.
Step 3: Detailed Solution:
When \(Br_2\) is added to phenol in water:
1. The phenol reacts with three molecules of \(Br_2\).
2. Bromine atoms replace the Hydrogen atoms at positions \(2\), \(4\), and \(6\).
3. The reaction equation is:
\[ C_6H_5OH + 3Br_2 \xrightarrow{H_2O} C_6H_2(OH)Br_3 + 3HBr \]
The resulting compound is \(2,4,6\)-tribromophenol, which is observed as a characteristic white precipitate.
Step 4: Final Answer:
The product formed is 2,4,6-Tribromophenol.