See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1: Identify the parent ring. The structure shown is a benzene ring with four substituents. Step 2: Identify the substituents on the ring by examining each group attached: - One carbon substituent that appears as -CH2CH3 (ethyl group) - Another -CH2CH3 (ethyl group) on an adjacent carbon - A -CH3 (methyl group) on the next carbon - A -CH2CH2CH3 (propyl group) on the next carbon Step 3: Number the ring to give the substituents the lowest possible locants. Starting from one of the ethyl-bearing carbons and proceeding around the ring to give the lowest set of locants to all substituents: - C1: ethyl - C2: ethyl - C3: methyl - C4: propyl This gives the locant set {1, 2, 3, 4}, which is the lowest possible. Step 4: List substituents in alphabetical order for the name, but assign numbers based on the numbering scheme: - 1,2-diethyl (two ethyl groups at positions 1 and 2) - 3-methyl (methyl at position 3) - 4-propyl (propyl at position 4) Step 5: Combine alphabetically with locants: diethyl (e), methyl (m), propyl (p) — alphabetical order is ethyl < methyl < propyl, so: 1,2-diethyl-3-methyl-4-propylbenzene. Step 6: Verify the name is consistent with the structure shown in the image — four substituents on a benzene ring at consecutive positions 1, 2, 3, 4 matching ethyl, ethyl, methyl, propyl respectively. Therefore, the correct answer is 1,2-diethyl-3-methyl-4-propylbenzene.