Question

Which is correct statement?

• A. o-nitrobenzoic acid is stronger than 3, 5 dinitrobenzoic acid in $H_{2}O$
• B. Branched carboxylic acids are more acidic than unbranched acids
• C. is stronger acid than
• D. Butanoic acid is stronger acid than succinic acid

Answer 1

Answer: (A)

[a] $o$-nitrobenzoic acid is the strongest acid among all the nitrobenzoic acids due to ortho effect and stabilization of carboxylate ion by nitro group.
[b] Branched carboxylic acids are less acidic than unbranched acids due to + $I$ -effect of alkyl groups.
[c] $o$-hydroxybenzoic acid is stronger acid than $o$-methoxybenzoic acid due to stabilization of carboxylate ion by $H$-bonding.
[d] Succinic acid is stronger acid than butanoic acid.
This is due to -$I$-effect of one carboxyl group on the other end.