JEE Main 2025 · 3 April · evening · Single correct · +4 / −1
What is the correct IUPAC name of
?
- (a) 3-Bromo-2-hydroxy-5-nitrobenzoic acid
- (b) 2-Hydroxy-3-bromo-5-nitrobenzoic acid
- (c) 3-Bromo-4-hydroxy-1-nitrobenzoic acid
- (d) 5-Nitro-3-bromo-2-hydroxybenzoic acid
Answer and solution
Answer (a) 3-Bromo-2-hydroxy-5-nitrobenzoic acid
Solution
Chemistry ma’am · 4 steps
The COOH carbon is C1, number towards the lower locant set, then write the prefixes in alphabetical order.
- Fix the parent. The -COOH group is the principal functional group, so the parent is benzoic acid. The ring carbon carrying -COOH is always C1.
- Choose the direction. Going from C1 towards -OH puts -OH at C2, -Br at C3 and -NO₂ at C5, giving {2, 3, 5}. Going the other way gives -NO₂ at C3, -Br at C5 and -OH at C6, giving {3, 5, 6}. The first point of difference is 2 < 3, so the first direction wins.
- Order the prefixes. Substituent prefixes are written in alphabetical order, not in locant order: bromo, hydroxy, nitro. Here -OH is a prefix because -COOH ranks higher.
- So. The name is 3-Bromo-2-hydroxy-5-nitrobenzoic acid, option (a).
The idea to keep. In a substituted benzoic acid, C1 carries the COOH. Pick the direction that gives the lowest locant set, then list the prefixes alphabetically, whatever their numbers are.
Answer from the NTA final answer key. Solution by PrepWiser.