See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1: Identify the structure. The compound is CH3-CH(OH)-CH(CH3)-CH(OH)-C(CH3)2-CH3. Written out, the carbon chain and substituents are: - C1: CH3 - C2: CH(OH) - C3: CH(CH3) - C4: CH(OH) - C5: C(CH3)2 - C6: CH3 Step 2: Identify the longest carbon chain. Counting the main chain carbons: CH3 (C1) - CH (C2) - CH (C3) - CH (C4) - C (C5) - CH3 (C6) = 6 carbons, so the parent chain is hexane. Step 3: Identify substituents and their positions. The OH groups are at C2 and C4 (diol). The methyl substituents are at C3, C5, and C5 (two methyls at C5). Step 4: Number the chain to give lowest locants to OH groups (principal characteristic groups). Numbering from the CH3 end closest to the first OH: - C1: CH3 - C2: CH(OH) → OH at position 2 - C3: CH(CH3) → methyl at position 3 - C4: CH(OH) → OH at position 4 - C5: C(CH3)2 → two methyls at position 5 - C6: CH3 Step 5: Name the compound. Parent chain = hexane; OH at 2,4 = hexane-2,4-diol; methyls at 3,5,5 = 3,5,5-trimethyl. Full name: 3,5,5-Trimethylhexane-2,4-diol. Step 6: Verify numbering gives lower locants. Numbering from the other end would place OH at positions 3 and 5, which is higher than 2 and 4. So numbering from the left is correct. Step 7: Why other options fail: - (b) 2,2,4-Trimethylhexane-3,5-diol: would require a different arrangement with gem-dimethyl at C2, which doesn't match the structure. - (c) and (d): these suggest a pentane parent chain with four methyl groups, but the correct longest chain is hexane (6 carbons). Therefore, the correct answer is A.