See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

Concept: The name 'bromomethylcyclopentane' can refer to any compound containing a cyclopentane ring with both a bromo substituent and a methyl substituent (interpreted as separate substituents on the ring), OR it can refer to (bromomethyl)cyclopentane where a -CH2Br group is attached to cyclopentane. We must enumerate all structural isomers that could legitimately carry this name, ignoring chirality. Step 1: Interpret the name broadly. 'Bromomethylcyclopentane' encompasses: A) (Bromomethyl)cyclopentane — the bromo is on the methyl group attached to cyclopentane: cyclopentane-CH2Br. This is 1 structure. B) Bromo + methyl both as ring substituents on cyclopentane (i.e., bromocyclopentane with a methyl group, or methylcyclopentane with a bromo group). Step 2: For case B, enumerate positional isomers of 1-bromo-1-methylcyclopentane, 1-bromo-2-methylcyclopentane, 1-bromo-3-methylcyclopentane (cis and trans count as different constitutional? No — ignoring chirality but cis/trans are different diastereomers, however the question says 'ignoring chirality' which typically means ignoring enantiomers but keeping diastereomers). Step 3: Enumerate: 1. (Bromomethyl)cyclopentane — CH2Br on ring, no ring Br 2. 1-bromo-1-methylcyclopentane — Br and CH3 on same carbon (C1) 3. 1-bromo-2-methylcyclopentane (cis) 4. 1-bromo-2-methylcyclopentane (trans) 5. 1-bromo-3-methylcyclopentane (cis) 6. 1-bromo-3-methylcyclopentane (trans) Note: 1-bromo-4-methylcyclopentane is same as 1-bromo-2-methylcyclopentane by ring symmetry, and 1-bromo-5-methyl is same as 1-bromo-2-methyl, so no new isomers there. Step 4: Count: structures 1 through 6 = 6 total isomers. Step 5: Why other options fail: - (a) 4: undercounts by missing cis/trans distinctions - (b) 5: undercounts one isomer - (d) 7: overcounts Therefore, the correct answer is C.