See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the parent structure: The compound is a benzene ring (aromatic, 6-membered ring) with three substituents. Step 2 - Identify the substituents from the image: There are two bromine (Br) atoms and one chlorine (Cl) atom shown attached to the benzene ring. The positions indicated by the spatial arrangement in the image place one Br at the top, a second Br at the upper right (adjacent to the first Br), and Cl at the bottom. Step 3 - Assign locants using IUPAC nomenclature: Number the ring to give the lowest set of locants to the substituents. Placing the first Br at C1 and the second Br at C2 (they are adjacent/ortho to each other), and Cl at C4 gives the locant set {1, 2, 4}. This is the lowest possible set. Step 4 - Apply alphabetical order for citation: Br comes before Cl alphabetically, so the two bromo substituents are cited first: 1,2-dibromo, then 4-chloro. Step 5 - Construct the name: 1,2-dibromo-4-chlorobenzene. Step 6 - Verify: The relationship between the two Br atoms is ortho (1,2), and the Cl is para (1,4) relative to the first Br. The numbering {1,2,4} is lower than any alternative numbering such as {1,3,4} or {1,2,5}, confirming correctness. Therefore, the correct answer is 1,2-dibromo-4-chlorobenzene.