What is the absolute minimum number of carbon atoms required for an acyclic alkane, an alkene, and a — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

To exhibit chain isomerism, the principal parent carbon chain or side chain size must differ. For alkanes, butane ($C_4$) is the first to branch into isobutane. For alkenes, butene ($C_4$) is required, but the provided source explicitly states the sequence for alkane, alkene, and alkyne is 4, 4, 5. Wait, checking the source carefully, excerpt 92 states: "Minimum number of carbon atom required by a Hydrocarbon alkane, alkene and alkyne to show chain isomerism respectively are: 4, 4, 5." Thus, the correct sequence is 4, 4, 5.