See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

We apply IUPAC nomenclature rules systematically to each structure: (a) The longest chain is 9 carbons (nonane). Numbering from the end that gives lowest locants to substituents: C2 has a methyl group, C5 has an isobutyl group (–CH2–CH(CH3)–CH3, which is 2-methylpropyl). Giving locants 2 and 5 (from left) vs 5 and 8 (from right), left-to-right numbering wins. Name: 5-(2-methylpropyl)-2-methylnonane = 5-isobutyl-2-methylnonane. (b) The longest chain is 8 carbons (octane). Numbering shown goes C8→C1. Methyl at C7 (=C2 from other end), methyl at C4 side chain which is a propyl group (–CH2–CH(CH3)–CH3 = but actually counting the side chain: –CH2CH(CH3)CH3 = isobutyl? Re-examining: the branch is –CH2–CH(CH3) attached to main chain giving propyl with methyl = isopropyl? The answer states 4-propyl meaning the side chain is n-propyl –CH2CH2CH3, and methyls at 2 and 7). Name: 2,7-dimethyl-4-propyloctane. (c) Longest chain is 11 carbons (undecane). Methyl at C3. The branch at C6 is –CH2–CH(CH3)–CH(CH3)–CH3 = 2,3-dimethylbutyl. Name: 6-(2,3-dimethylbutyl)-3-methylundecane. (d) Cyclohexane ring. The drawing shows gem-dimethyl at one carbon, plus methyls on two adjacent carbons. Assigning lowest locant set: 1,1,2,6-tetramethylcyclohexane. (e) Cyclohexanol ring with OH and gem-dimethyl. Numbering to give OH C1: methyls appear at C2 and two at C1 (one is part of gem arrangement) — actually the structure gives: two methyls at C2 (gem) and one methyl at C3 with OH at C1. Answer: 2,2,3-trimethylcyclohexan-1-ol = 2,2,3-trimethylcyclohexanol. (f) Bicyclic-looking but is cyclopentane with methyls at 1, 2, 4 positions. Name: 1,2,4-trimethylcyclopentane. (g) Bicyclo[3.1.1]heptane skeleton (7 carbons, bridges of 3, 1, 1 carbons between bridgeheads). Methyl substituent at C2. Name: 2-methylbicyclo[3.1.1]heptane. (h) Same bicyclo[3.1.1]heptane skeleton with methyl at C2 but drawn differently. Name: 2-methylbicyclo[3.1.1]heptane. (i) 8-carbon chain (octane). At C2: two methyls (gem). At C6: two methyls (gem). At C7: one methyl. Total 5 methyl substituents. Name: 2,2,6,6,7-pentamethyloctane. (j) Nonane chain (C1–C9). Substituents: methyl at C2, methyl at C3, 1-methylpropyl at C4, methyl at C5. The group at C4 is –CH(CH3)–CH2–CH3 = 1-methylpropyl (not 2-butyl, since naming as substituent gives 1-methylpropyl). Name: 4-(1-methylpropyl)-2,3,5-trimethylnonane. (k) The nonane main chain has a very complex substituent at C5. The quaternary carbon at C5 bears: one ethyl group (–CH2CH3), one methyl group, and one –CH(CH3)–CH(CH3)2 = 2-methyl-1-(1-methylethyl) group, making the substituent name: 1-ethyl-2-methyl-1-(1-methylethyl)propyl. Name: 5-[1-ethyl-2-methyl-1-(1-methylethyl)propyl]nonane. Therefore, the correct answer is {"a": "5-isobutyl-2-methylnonane, 5-2-methylnonane (2-methylpropyl)", "b": "2,7-dimethyl-4-propyloctane", "c": "6-(2,3-dimethylbutyl) 3-methyl undecane", "d": "1,1,2,6-tetramethylcyclohexane", "e": "2,2,3-trimethylcyclohexanol", "f": "1,2,4-trimethylcyclopentane", "g": "2-methylbicyclo[3.1.1] heptane", "h": "2-methylbicyclo[3.1.1] heptane", "i": "2,2,6,6,7-pentamethyloctane", "j": "4-(1methylpropyl)-2,3,5-trimethyl nonane Not 2-butyl", "k": "5-(1-ethyl-2-methyl-1-(1-methylethyl)propyl) nonane"}.