See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step-by-step IUPAC naming for each compound: (a) Structure: CH3-CH2-CH(CH3)-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH(CH3)-CH3 Count the longest chain: starting from the left CH3, we have 13 carbons in the main chain (tridecane). The methyl groups are at positions 2 and 11 when numbered to give lowest locants (numbering from the end nearest the first branch: C1=CH3, C2=CH(CH3), ..., C12=CH(CH3), C13=CH3). Checking: from left end position 2 has methyl; from right end position 2 has methyl; symmetric, so 2,11-dimethyltridecane. (b) Structure: CH3-CH2-CH(OH)-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH(CH3)-CH3 Longest chain: 13 carbons. Principal characteristic group is OH (alcohol), so suffix -ol. Number to give OH lowest locant: OH is on C3 from the left (C3), methyl branch is on C12 from the left end. Name: 12-methyltridecan-3-ol. Verify: from right end, OH would be at C11, methyl at C2; from left, OH at C3, methyl at C12. Lower locant set is {3,12} vs {2,11}; since the principal group (OH) gets priority for lowest locant, we choose numbering giving OH=C3. Hence 12-methyltridecan-3-ol. (c) Structure analysis: The structure shows a cross-shaped branching. The longest continuous chain must be identified. The four arms are: top-left chain: CH3-CH2-CH2-CH2- (4C), top-right: -CH2-CH3 (2C), bottom via CH: -CH2-CH3 (2C), and -CH3 on the central CH. Redrawing: central bond CH-CH with substituents: one CH has n-propyl (CH2CH2CH3) and ethyl (CH2CH3) from the written structure; the other CH has methyl (CH3) and ethyl from the bottom chain. Longest chain = octane (8C). Substituents: 3-methyl and 4-ethyl on octane. IUPAC: 4-ethyl-3-methyloctane. (d) Cyclopentadecane (15-membered ring). Substituents: one CH3 at a ring carbon (call it C1), an adjacent carbon (C2) bears a CH3, and another ring carbon (C7) bears a CH3 (the one shown at top right of ring). Numbering to give lowest locants: 1,2,7-trimethylcyclopentadecane. (e) Cyclopentane ring. One ring carbon bears two CH3 groups (gem-dimethyl), an adjacent ring carbon bears one CH3, and another ring carbon (at position 5 relative to the gem-dimethyl) bears one CH3. Numbering: the carbon with two methyls is C1 (1,1-dimethyl), adjacent carbon with one methyl is C2 (2-methyl), and the carbon at position 5 (non-adjacent) with one methyl is C5 (5-methyl). IUPAC name: 1,1,2,5-tetramethylcyclopentane. Therefore, the correct answer is {"a": "2,11-dimethyltridecane", "b": "12-methyl-tridecan-3-ol", "c": "4-ethyl-3-methyloctane", "d": "1,2,7-trimethylcyclopentadecane", "e": "1,1,2,5-tetramethylcyclopentane"}.