Chemistry Alcohols & Phenols PMDC 2020
PMDC Verified Question 63 of 95
Phenol is more acidic than alcohols because of the following reason
A
Delocalization of negative charge in the OH group
B
Delocalization of positive charge on the carbon atom in ring
C
Delocalization of negative charge in the ring
D
Delocalization of positive charge in the OH group
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Delocalization of negative charge in the ring
Concept:

Acidity relies heavily on the resonance stabilization of the resulting conjugate base.

Formula:

Not applicable to this conceptual question.

Solution:

  • When phenol donates a proton, it forms the phenoxide ion (\(\text{C}_6\text{H}_5\text{O}^-\)).


  • The negative charge left on the oxygen atom is delocalized (spread out) into the \(\pi\)-system of the aromatic ring through resonance.


  • This delocalization of negative charge in the ring vastly stabilizes the ion, making the forward acidic reaction highly favorable compared to aliphatic alcohols (which cannot delocalize).


Why other options are incorrect:

The charge is negative, not positive (rules out B and D). The delocalization happens away from the OH group and into the aromatic ring, making Option A technically inaccurate.

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