Question

Given are cyclohexanol `(I)`, acetic acid `(II),2,4,6-`trinitrophenol `(III)` and phenol `(IV)`. In these the order of decreasing acidic character will be:
A. `III gt IV gt II gt I`
B. `III gt II gt IV gt I`
C. `II gt III gt I gt IV`
D. `II gt III gt IV gt I`

Answer 1

Correct Answer - B
Carboxylic acids are stronger acids relative to phenols which are stronger acids than aliphatic alcohols. But we can increase the acidic strength of phenols by introducing electron withdrawing groups. On account of the presence of three electron withdrawing groups. `NO_(2)` groups, the `2,4,6-`trinitrophenol is a very strong acid characterzed by a very large dissociation constant `(K_(a))`. Thus, the correct order of acidic strength is `2,4,6-`trinitrophenol `(III)` `gt` acetic acid `(II)` `gt` phenol (IV) `gt` cyclohexanol