The increasing order of acidity of the following carboxylic acids is
The increasing order of acidity of the following carboxylic acids is
III < IV < II < I
II < III < IV < I
I < II < IV < III
III < IV < I < II
Solution
(i) $\mathrm{NO}_2$ group increases the acidic nature due to - I effect.
(ii) $\mathrm{OCH}_3$ and $\mathrm{CH}_3$ are electron donating groups (i.e., $+\mathrm{I}$ effect), thus decreases the acidic nature, but $\mathrm{OCH}_3$ will decrease acidic nature more than of $\mathrm{CH}_3$ group Hence, correct order is III $ < $ IV $ < $ I $ < $ II
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