See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 – Identify the parent chain and functional groups. The molecule contains three ketone (C=O) groups. We need to find the longest continuous carbon chain that includes all three carbonyl carbons. Step 2 – Trace the longest chain. Starting from the terminal methyl of one acetyl group, trace through: CH3–C(=O)–CH(CH3)–CH2–C(=O)–CH2–CH2–CH2–CH2–CH(C2H5)–C(=O)–CH3. Counting carbons along this backbone: C1(CH3)–C2(C=O)–C3(CH with methyl branch)–C4(CH2)–C5(C=O)–C6(CH2)–C7(CH2)–C8(CH2)–C9(CH with ethyl branch)–C10(C=O)–C11(CH3). This gives an 11-carbon chain → parent chain: undecane. Step 3 – Identify substituents and their positions. - Ketone oxygens at C2, C5, and C10 → trione suffix: undecane-2,5,10-trione. - Methyl branch at C3. - Ethyl branch at C9. Step 4 – Assign lowest locants. Numbering from left (C1 = terminal CH3 of first acetyl) gives substituents/carbonyl at 2,3,5,9,10. Numbering from right gives 2,3,7,9,10. Left-to-right numbering gives the lower set at first point of difference (position 3 methyl vs position 9 ethyl; 3 < 9), confirming the chosen direction. Step 5 – Compile the IUPAC name. Parent chain: undecane (11 carbons). Ketones: 2,5,10-trione. Substituents: 3-methyl, 9-ethyl. Alphabetical order: ethyl before methyl. Full name: 9-ethyl-3-methylundecane-2,5,10-trione. No alternative options are provided, so no elimination is required. Therefore, the correct answer is 9-ethyl-3-methylundecane-2,5,10-trione.