Let's analyze the problem step-by-step: ### Step 1: Understand the Terminology - **Exo attack:** H⁻ attacks from the **top face** of the ring. - **Endo attack:** H⁻ attacks from the **bottom face** of the ring. ### Step 2: Analyze the Products Formed - **Compound 1**: The OH group is on carbon 2 (axial), and the new hydrogen (from reduction) is on carbon 1 (equatorial). - **Compound 3**: The OH group is on carbon 2 (equatorial), and the new hydrogen is on carbon 1 (axial). ### Step 3: Assign Attack Faces - If H⁻ attacks from the **exo (top) face**, it will add from above, putting the hydrogen above the ring (axial position on carbon 1). - If H⁻ attacks from the **endo (bottom) face**, it will add from below, putting the hydrogen below the ring (equatorial position on carbon 1). ### Step 4: Relate to the Products - In **Compound 1**, the hydrogen is **equatorial** at C-1 (which is below the ring), so it comes from an **endo attack** (bottom face). - In **Compound 3**, the hydrogen is **axial** at C-1 (which is above the ring), so it comes from an **exo attack** (top face). ### Step 5: Fill in the Answers - **Compound 1:** Formed by **endo** attack of H⁻. - **Compound 3:** Formed by **exo** attack of H⁻. --- ## **Final Answer** > Based on this information, Compound 1 is formed by an **endo** attack of H⁻, and Compound 3 is formed by an **exo** attack of H⁻. --- **Summary Table:** | Compound | Attack Type | Face | H Position (C-1) | |----------|-------------|-------------|------------------| | 1 | Endo | Bottom | Equatorial | | 3 | Exo | Top | Axial |