See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1: Identify the principal characteristic group. The compound has two functional groups: a nitrile (CN) and a carboxylic acid (COOH). In IUPAC nomenclature, carboxylic acid has higher seniority than nitrile, so COOH is the principal characteristic group and gives the suffix '-oic acid'. Step 2: Count the longest carbon chain including the principal characteristic group carbon. The chain is: NC–CH2–CH2–COOH. Counting carbons: C1 (COOH carbon), C2 (CH2), C3 (CH2 bearing CN). That gives a 3-carbon chain (propanoic acid backbone). Step 3: The CN group is a substituent (cyano group) attached at C3. Since COOH carbon is C1, the CH2 adjacent to COOH is C2, and the CH2 bearing the CN is C3. Step 4: Name the compound. Parent chain = propanoic acid (3 carbons including COOH). Substituent = cyano at position 3. IUPAC name = 3-Cyanopropanoic acid. Step 5: Evaluate other options. (a) 3-Carboxy propanenitrile — this would make CN the principal group and COOH a substituent, which is incorrect since COOH has higher priority. (b) 4-Cyanobutanoic acid — implies a 4-carbon chain for the acid part, which would require an extra carbon not present here. (c) 2-Cyanoethane Carboxylic acid — not a standard IUPAC format and the locant is incorrect. (d) 3-Cyanopropanoic acid — correct as derived above. Therefore, the correct answer is D.