Let's break down problem step by: ## ** 1: Enantiomers- **Enomers** are pairs of molecules that are non-superimposable mirror images of each other. - They must have **chiral centers** (carbon atoms with four different groups attached). - The arrangement of the groups around the chiral center is opposite in each molecule. --- ## **Step 2: Analyze Each Pair** ### **Pair A** - **Left Molecule:** - Groups: CH₃, HOOC, OH, H - **Right Molecule:** - Groups: COOH, HO, CH₃, H **Mirror Check:** If you draw a mirror line, the positions of the groups are swapped exactly as expected for enantiomers: - CH₃ ↔ COOH - HOOC ↔ HO - OH ↔ CH₃ - H ↔ H **Conclusion:** **These look like enantiomers.** --- ### **Pair B** - **Left Molecule:** - Groups: CH₂CH₃, Cl, H, Br - **Right Molecule:** - Groups: Br, H, Cl, CH₂CH₃ **Mirror Check:** After drawing a mirror, the groups are swapped: - CH₂CH₃ ↔ Br - Cl ↔ H - H ↔ Cl - Br ↔ CH₂CH₃ However, the priorities are not swapped correctly; these actually look like identical structures rotated, **not mirror images**. **Conclusion:** **Not enantiomers.** --- ### **Pair C** - **Left Molecule:** - Groups: HO, H, CH₂CH₃, CH₃ - **Right Molecule:** - Groups: HO, H, CH₂CH₃, CH₃ Both structures are identical; no mirror image difference. **Conclusion:** **Not enantiomers.** --- ## **Step 3: Final Answer** ### **Final Answer** > **Pair A** are enantiomers. --- ## **Summary Table** | Pair | Enantiomers? | Reason | |------|--------------|------------------------------| | A | Yes | Non-superimposable mirrors | | B | No | Identical, not mirrors | | C | No | Identical, not mirrors | --- **So, the answer is:** ## **A is the pair of enantiomers.**