1
The correct acidic order of the following is [figure]
- I > II > III
- III > I > II
- II > III > I
- I > III > II
Answer
(2) III > I > II
Solution
Acidity of phenols depends on the stability of the phenoxide ion.
III: -NO2 at the para position withdraws electrons (−R and −I effects) and stabilises the phenoxide ion ⇒ most acidic.
II: -CH3 at the para position releases electrons (+I and hyperconjugation) and destabilises the phenoxide ion ⇒ less acidic than phenol.
∴ Acidic order: III > I > II
Answer: (2)
AIPMT 2001