JEE Main 2026 — General Organic Chemistry Question with Solution

The correct order of decreasing priority for functional groups in IUPAC nomenclature is:

Carboxylic acids ($-COOH$) $>$ Sulphonic acids ($-S{O}_{3}H$) $>$ Esters ($-COOR$) $>$ Acid halides ($-COX$) $>$ Amides ($-CON{H}_2$) $>$ Nitriles ($-CN$) $>$ Aldehydes ($-CHO$) $>$ Ketones ($>C=O$) $>$ Alcohols ($-OH$) $>$ Thiols ($-SH$) $>$ Amines ($-N{H}_2$) $>$ Alkynes ($-C\equiv C-$).

Checking the given options:
Option (A) is incorrect because $-CHO$ has a higher priority than $>C=O$.
Option (B) is incorrect because $-COOC{H}_3$ has a higher priority than $-CON{H}_2$.
Option (C) correctly follows the priority order: $-CON{H}_2>-CHO>>C=O>-N{H}_2>-C\equiv C-$.
Option (D) is incorrect because $-CN$ has a higher priority than $-CHO$.

Answer: $-CON{H}_2,-CHO,>C=O,-N{H}_2,-C\equiv C-$