Q. Arrange the following compounds in the increasing order of their acidic strength
i. -nitrophenol
ii. -cresol
iii. phenol
iv. -chlorophenol

 4331  178 KCETKCET 2015Alcohols Phenols and Ethers Report Error

Solution:

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m-cresol has an electron releasing group (CH3). Hence, it decreases the acidic strength .Both nitro and chloro are having -I-effect. Hence, they show higher acidic strength. But nitro is a stronger -I-group than chloro group. Hence, m-nitro phenol is more acidic than m-chlorophenol.

So increasing order of acidic strength is II < III < IV < I.