See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Three-Membered Cyclic Compounds (Epoxides/Aziridines) - Strain Analysis **Step 1: Identify the three-membered ring geometry** Three-membered rings (cyclopropane, epoxide, aziridine) have C-C-C or C-O-C bond angles of approximately **60°**, far smaller than the ideal tetrahedral angle of **109.5°**. **Step 2: Analyze angle strain** The compressed **60° angles** create significant **angle strain** (option B). Bonds are forced into non-ideal geometries, destabilizing the ring structure. **Step 3: Analyze torsional strain** In cyclopropane, adjacent C-H bonds are **eclipsed** rather than staggered. This creates unfavorable **torsional strain** (option A) from electron repulsion between overlapping orbitals. **Step 4: Analyze steric strain** The tight three-membered ring creates **van der Waals repulsion** between atoms that are forced close together, causing **steric strain** (option C). **Step 5: Conclusion** All three types of strain operate simultaneously in three-membered rings: - High angle strain (60° vs 109.5°) - High torsional strain (eclipsed conformations) - High steric strain (crowded ring) The cumulative effect makes these rings highly reactive and prone to ring-opening reactions. **Answer: (D) All of these**