Let's analyze the question step by step: ## **Step 1: Identify the Reference Molecule** The reference molecule is **Molecule 1**: - It shows a central carbon with four different groups: Br, OH, H, and CH₃ (methyl). ## **Step 2: What is an Enantiomer?** - **Enantiomers** are non-superimposable mirror images of each other. - For a tetrahedral carbon (chiral center), enantiomers have opposite configurations (R/S). ## **Step 3: Assign the Configuration for Molecule 1** Let’s assign priorities based on Cahn–Ingold–Prelog rules: 1. Br (highest atomic number) 2. OH 3. CH₃ 4. H (lowest, always in the back if possible) If you orient the molecule with H in the back and move from 1 → 2 → 3, if it’s clockwise, it’s **R**; if counterclockwise, it’s **S**. Looking at Molecule 1: - Br (top right), OH (top left), H (bottom left), CH₃ (bottom right). - If H is in the back, the order from Br → OH → CH₃ is **clockwise**: **R configuration**. ## **Step 4: Find the Enantiomer** We need to find a molecule with the **S configuration** (the exact mirror image). ## **Step 5: Analyze Each Molecule** - **Molecule 2:** (Br, OH, H, CH₃) - Br (top right), OH (top left), H (bottom right), CH₃ (bottom left) - Comparing with Molecule 1, the positions of H and CH₃ are swapped. - This is the **mirror image** (S configuration). - **Molecule 3:** (Br, H, OH, CH₃) - Br (top right), H (top left), OH (bottom left), CH₃ (bottom right) - This is not the mirror image; it's a different arrangement. - **Molecule 4:** (Br, OH, CH₃, H) - Br (top left), OH (top right), CH₃ (bottom left), H (bottom right) - Not the mirror image. - **Molecule 5:** (Br, HO, H, CH₃) - Same as Molecule 2. It’s the **enantiomer**. - **Molecule 6:** (Br, CH₃, OH, H) - Br (top left), CH₃ (top right), OH (bottom left), H (bottom right) - Not the mirror image. ## **Step 6: Final Answer** The enantiomer of Molecule 1 is **Molecule 2** (and Molecule 5, which appears to be a duplicate of Molecule 2). --- ## **Summary Table** | Molecule | Enantiomer of 1? | |------------|------------------| | Molecule 1 | No (reference) | | Molecule 2 | **Yes** | | Molecule 3 | No | | Molecule 4 | No | | Molecule 5 | **Yes** (same as 2)| | Molecule 6 | No | --- ### **Final Answer** **Molecule 2** (and Molecule 5, if allowed to select more than one) are enantiomers of Molecule 1. If you can only select one, choose **Molecule 2**. If you can select both, choose **Molecule 2 and Molecule 5**.