See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structure: The compound is CH3-C(CH3)2-CH(CH3)-CH(I)-CH2-CH3. The quaternary carbon bears two methyl groups (the CH3 at the start of the chain and the substituent CH3), the next carbon bears one methyl group, and the fourth carbon bears iodine. Step 2 - Find the longest carbon chain: Count the carbons in the main chain. Starting from the terminal CH3 through C(CH3)2, CH(CH3), CH(I), CH2, CH3 gives 6 carbons total in the main chain — this is a hexane backbone. Step 3 - Number the chain to give substituents the lowest locants: Numbering from the end closest to the substituents: C1=CH3, C2=C(CH3)2, C3=CH(CH3), C4=CH(I), C5=CH2, C6=CH3. This gives substituents at positions 2,2,3 (three methyls) and 4 (iodo). Step 4 - Name the compound: The parent chain is hexane (6 carbons). There are two methyl groups at C2 (2,2-dimethyl) and one methyl group at C3 (3-methyl), giving 2,2,3-trimethyl. Iodine is at C4, giving 4-iodo. Combined: 4-Iodo-2,2,3-trimethylhexane. Step 5 - Verify numbering from the other end: If numbered from the other end, iodo would be at C3 and methyls at C4,4,5 — locant set {3,4,4,5} vs {2,2,3,4} — the latter is lower at first point of difference (2 < 3), so numbering as chosen is correct. Step 6 - Eliminate wrong options: (a) 3-Iodo-4,5,5-trimethylhexane — wrong positions; (b) 4-Iodo-1,1,3-trimethylhexane — positions 1,1 are impossible for internal methyls on a hexane with this structure; (c) 4-Iodo-2,2-dimethylheptane — heptane would require 7 carbons in the main chain, but the longest chain is 6. Therefore, the correct answer is D.