See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the parent structure: The molecule is a benzene ring, so the parent name is 'benzene'. Step 2 - Identify all substituents: There is one methyl group (-CH3) and three nitro groups (-NO2) attached to the ring. Step 3 - Locate positions of substituents on the ring: The methyl group is at one carbon. The two nitro groups flanking the methyl are at the adjacent carbons (ortho positions), and the third nitro group is at the carbon directly opposite (para to the methyl). This gives a 1,3,5 arrangement for the three nitro groups and position 2 (between two nitro groups) for the methyl — or equivalently, methyl at C1 (position 1), nitro groups at C2 (ortho), C6 (ortho), and C4 (para) relative to methyl, which is the same as nitro at 1,3,5 and methyl at 2 when numbered to give lowest locants. Step 4 - Apply IUPAC numbering for lowest locants: Assign C1 to the methyl-bearing carbon. The nitro groups are then at C2, C4, and C6... but to minimize locant set, we renumber so the three nitro groups are at 1, 3, 5 and the methyl is at 2. Locant set {1,2,3,5} vs {1,2,4,6} — the set {1,2,3,5} is lower. So: nitro at C1, methyl at C2, nitro at C3, nitro at C5 → name is 2-methyl-1,3,5-trinitrobenzene. Step 5 - Construct the name: Principal substituents listed alphabetically — methyl and nitro. With nitro groups at 1,3,5 and methyl at 2: 2-methyl-1,3,5-trinitrobenzene. This compound is commonly known as TNT (2,4,6-trinitrotoluene), but the systematic IUPAC name with benzene as parent is 2-methyl-1,3,5-trinitrobenzene. Therefore, the correct answer is 2-methyl-1,3,5-trinitrobenzene.