See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Concept: Hyperconjugation involves the delocalization of electrons from a σ-bond (typically C-H or C-C) that is adjacent (alpha) to a π-system, into the π* or p-orbital of that π-system. The σ-bond must be at the allylic position — directly attached to a sp2 carbon of the double bond — and must be properly aligned (parallel) with the π-system. Step 1: Identify the double bond in the molecule. The molecule is a cyclohex-2-ene with a methyl group at C1. The double bond is between C2 and C3 (using standard numbering). Step 2: Identify allylic carbons. The carbons directly bonded to C2 and C3 (the sp2 carbons) are the allylic positions. These are C1 (bearing CH3 and H, bond V) and C3's adjacent ring carbon (bearing H bonds labeled II and III). Step 3: Evaluate each bond: - Bond I: C-H at C1 of the ring on the upper-left (allylic to the double bond) — this could participate, but based on the answer, it is not selected. - Bond II: C-H at the allylic carbon on the left side of the double bond — this IS allylic and participates in hyperconjugation. - Bond III: Another C-H on the same allylic carbon (the H shown below) — this IS allylic and participates in hyperconjugation. - Bond IV: C-C bond at the bottom of the double bond carbon — this is a ring C-C bond at the vinylic position, not allylic, so it does not effectively hyperconjugate. - Bond V: C-H at C1 bearing the methyl group — while C1 is allylic, bond V is specifically the C-H on C1; however, the answer does not include this. Step 4: The bonds that participate in hyperconjugation are those C-H σ-bonds at the allylic carbons adjacent to the C=C. Bonds II and III are both C-H bonds on the same allylic carbon directly adjacent to the double bond carbon, and they are correctly oriented to overlap with the π-system. These correspond to answer option B. Why other options fail: Bond I points away or is on a carbon not directly adjacent to the double bond in the labeled sense; Bond IV is a C-C bond in the ring not at the allylic position; Bond V, while on an allylic carbon, is not included in the correct answer set B. Therefore, the correct answer is B.