Organic Chemistry Basics 2 Question 43
43. In the following compounds
(1997)
(I)
(II)
(III)
(IV) The order of acidity is
(a) III $>$ IV $>$ I $>$ II
(b) I $>$ IV $>$ III $>$ II
(c) II $>$ I $>$ III $>$ IV
(d) IV $>$ III $>$ I $>$ II
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Solution:
- Nitro group from para position exert electron withdrawing resonance effect, increases acidity of phenol the most. This is followed by meta nitrophenol in which nitro group exert electron withdrawing effect on acidity. $\mathrm{CH}_{3}-$ is an electron donating group, decreases acid strength. Hence, the overall order is
$$ \text { IV }>\text { III }>\text { I }>\text { II } $$
