Chemistry Alcohols & Phenols SZABMU 2024
PMDC Verified Question 5 of 95
The anion derived by deprotonation of an alcohol acts as ____
A
Acidic moiety
B
Lewis acid
C
Electrophile
D
Lewis base
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Lewis base
Concept:

When an alcohol loses its acidic proton, it forms an alkoxide ion (\(\text{RO}^-\)).

Formula:

$$ \text{R-O-H} \longrightarrow \text{R-O}^- + \text{H}^+ $$

Solution:

  • The alkoxide ion has a full negative charge and three lone pairs of electrons on the oxygen atom.


  • Because it is electron-rich and readily donates an electron pair to form a bond (acting as a nucleophile), it perfectly fits the definition of a Lewis base (an electron-pair donor).


Why other options are incorrect:

A Lewis acid is an electron-pair acceptor (alkoxides repel electrons). An electrophile is electron-deficient. The anion is the conjugate base, not an acidic moiety.

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