Concept:Acidic strength is dictated by the stability of the conjugate base. Greater resonance or lack of destabilizing electron-donating groups leads to higher acidity.
Solution:- Carboxylic Acids: Extremely stable carboxylate ion via identical resonance structures. (Strongest)
- Phenol: Phenoxide ion stabilized by resonance into the aromatic ring, but less stable than carboxylate.
- Water: Forms hydroxide ion. No resonance, but no destabilizing alkyl groups either.
- Alcohol: Forms alkoxide ion. The alkyl group pushes electrons (\( +I \) effect) onto the already negative oxygen, heavily destabilizing it. (Weakest)
Why other options are incorrect:Option B is the only chemically accurate sequence recognizing water as a stronger acid than unsubstituted aliphatic alcohols.
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