See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Solution: Identifying Superimposable Structures **Superimposable structures** are identical molecules that can be perfectly overlaid; they're mirror images that are superimposable (not enantiomers). ## Analysis of Each Structure: **Structure I:** Br, Me, HO, Et around a stereocenter - Configuration: Br (front-right), HO (back-left), Me (bottom), Et (left) **Structure II:** Br, H, Et, OH, Me around a stereocenter - Configuration: Br (front), H (front-right), Et (back-right), OH (back-left), Me (bottom) **Structure III:** Br, Me, Et, H, OH around a stereocenter - Configuration: Br (front), Me (front-right), Et (back-right), H (front-left), OH (back-left) **Structure IV:** Br, Me, HO, Et around a stereocenter - Same four groups as Structure I but in different positions ## Checking Superimposability: **II and III:** When we assign priorities and compare configurations: - Both have the same four groups: Br, OH, Et, Me (and H in II) - Rotating/flipping Structure II appropriately overlays it perfectly on Structure III - **They are identical molecules (superimposable)** **I and II:** Different connectivity (I has no H attached to the chiral center in the same way), so not superimposable. **I and IV:** Different spatial arrangements despite same groups. **The answer is (B) II and III** — these structures are superimposable as they represent the same molecule in different orientations.