See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Chain Isomerism vs Position Isomerism in Alkanes **Chain Isomerism:** - Occurs when the carbon skeleton can be arranged differently - **Minimum requirement: 4 carbons** - Example: $C_4H_{10}$ has two isomers: - n-butane: $CH_3-CH_2-CH_2-CH_3$ (straight chain) - Isobutane: $CH_3-CH(CH_3)-CH_3$ (branched chain) **Position Isomerism:** - Occurs when a functional group or substituent can be positioned at different locations on the same carbon chain - **Minimum requirement: 5 carbons** - Example: $C_5H_{12}$ has positional isomers: - 1-pentane (or n-pentane) - 2-methylbutane (methyl group at different position) With **3 carbons or fewer**, you cannot have different arrangements of the main chain or different positions for substituents. **Answer: (1) 4, 5** ✓