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Which one of the following compounds is most acidic?
Options:
- A
- B
- C
- D
Solution:
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Verified Answer
The correct answer is:
Phenols are more acidic than alcohols, due to the stabilization of phenoxide ion via resonance.
Ortho nitrophenol is most acidic of all because $-\mathrm{NO}_2$ is a electron withdrawing group. Thus, $\mathrm{NO}_2$ stabilise of negative charge on the oxygen of phenoxide ion. On the other hand, $\mathrm{CH}_3$ group is a electron donating group. Thus, acidic strength of phenol is decreased in cresol due to destabilisation of phenoxide ion.
Thus, correct order is:
Caution
$\Rightarrow$ Phenoxide ion is stabilized due to following resonating structures:
Ortho nitrophenol is most acidic of all because $-\mathrm{NO}_2$ is a electron withdrawing group. Thus, $\mathrm{NO}_2$ stabilise of negative charge on the oxygen of phenoxide ion. On the other hand, $\mathrm{CH}_3$ group is a electron donating group. Thus, acidic strength of phenol is decreased in cresol due to destabilisation of phenoxide ion.
Thus, correct order is:
Caution
$\Rightarrow$ Phenoxide ion is stabilized due to following resonating structures:
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