question_answer

Correct increasing order of acidity of the following phenols is

A)  

B)  

C)  

D)  

Correct Answer: C

Solution :

Phenols are stronger acids than alcohols, because phenols are considered as resonance hybrid of the following structures As a result of resonance, the \[O\] atom acquires a partial positive charge. This weakens the \[O-H\] bond and facilitates the release of proton. Thus, phenols are more acidic than alcohols. Now, any electron withdrawing group (\[-N{{O}_{2}}\] group) which stabilize the phenoxide ion by dispersing the negative charge relative to phenol, increases the acidic strength of phenol, whereas any electron donating group (\[-C{{H}_{3}}\]group) which destabilize the phenoxide ion by intensifying the negative charge relative to phenol tend to decrease the acidic strength of phenols. Thus, the correct order of acidity.