See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Chain and Position Isomerism in Alkynes **Chain Isomerism:** - Occurs when the main carbon chain can be arranged differently - For alkynes ($C_nH_{2n-2}$), minimum **5 carbons** needed - Example: $C_5H_8$ gives pent-1-yne (linear) vs 2-methylbut-1-yne (branched) - With 4 carbons: only but-1-yne possible (no branching alternative) **Position Isomerism:** - Occurs when the triple bond can be positioned at different locations - For alkynes, minimum **6 carbons** needed - Example: $C_6H_{10}$ gives hex-1-yne, hex-2-yne, hex-3-yne (different triple bond positions) - With 5 carbons: only pent-1-yne and pent-2-yne possible, but these don't show true position isomerism as distinct from chain isomerism **Answer: (3) 4, 6** - **4 carbons** minimum for chain isomerism - **6 carbons** minimum for position isomerism