See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the parent structure: The compound contains a benzene ring as the parent aromatic system. Step 2 - Identify all substituents on the ring: a) At position 1: a -COOH (carboxylic acid) group b) At position 2 (ortho to COOH): a -SO3H (sulfonic acid) group c) At position 4 (para to COOH): a -CHO (aldehyde/formyl) group Step 3 - Establish numbering and principal characteristic group: In IUPAC nomenclature, the carboxylic acid (-COOH) is the principal characteristic group and gets the lowest locant (C1). The ring is then numbered to give the next substituents the lowest possible locants. Step 4 - Assign locants: With -COOH at C1, the -SO3H is at C2 (ortho), and -CHO is at C4 (para). This gives locants 1, 2, 4. Step 5 - Build the name: The parent chain is benzoic acid (benzene + COOH). The CHO substituent on the ring is named as 'formyl' (as a prefix when COOH is the principal group). The SO3H group is named 'sulpho'. Combining: 4-formyl (CHO at C4) + 2-sulpho (SO3H at C2) + benzoic acid = 4-formyl-2-sulphobenzoic acid. Therefore, the correct answer is 4-formyl-2-sulphobenzoic acid.