Assertion (A): p-nitrophenol is more acidic than phenol. Reason (R): Nitro group is an electron-withdrawing group; it stabilizes phenoxide ion by dispersal of negative charge.
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Electron-withdrawing groups increase phenol acidity.
Order: Nitro phenol>Phenol>Alkyl phenol
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
Assertion (A) is true, but Reason (R) is false.
Assertion (A) is false, but Reason (R) is true.
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The Correct Option isA
Solution and Explanation
Step 1: Analyze Assertion (A).
p-Nitrophenol contains a nitro group (\(-NO_2\)) at the para position.
This increases acidity compared to phenol.
\(\Rightarrow\) Assertion is true.
Step 2: Analyze Reason (R).
The nitro group is strongly electron-withdrawing due to:
\(-I\) effect (inductive)
\(-R\) effect (resonance)
It stabilizes the phenoxide ion by delocalizing negative charge over the nitro group.
Step 3: Logical connection.
The increased stability of conjugate base directly increases acidity.
\[
\therefore \text{Both A and R are true and R explains A}
\]
