2022 Alcohols, Phenols and EthersAcidity of Phenols – Effect of Substituents Medium Question 1 of 2 in Acidity of Phenols – Effect of Substituents

Given below are two statements:
Statement I: The acidic strength of monosubstituted nitrophenol is higher than phenol because of electron withdrawing nitro group.
Statement II: o-nitrophenol, m-nitrophenol and p-nitrophenol will have same acidic strength as they have one nitro group attached to the phenolic ring. In the light of the above statements, choose the most appropriate answer from the options given below:

A Statement I is incorrect but Statement II is correct
B Both Statement I and Statement II are correct
C Both Statement I and Statement II are incorrect
D Statement I is correct but Statement II is incorrect

The answer is D.

Solution

The acidic strength of phenol increases due to electron-withdrawing groups, so nitrophenols are more acidic than phenol – Statement I is correct.
Order of acidic strength: p-nitrophenol > o-nitrophenol > m-nitrophenol > phenol, so they do not have the same acidic strength – Statement II is incorrect.

Concept acidity of nitrophenols

Acidity of Phenols – Effect of Substituents in past papers

2 questions from this chapter have appeared across 2 exam years.