See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Stability Analysis of Methylcyclopropane Isomers These are methylcyclopropane isomers. Their stability depends on **1,3-diaxial strain** and **ring strain** in the cyclopropane system. ## Step-by-Step Analysis: **Structure Identification:** - **(I)** Me axial, H axial → severe 1,3-diaxial strain - **(II)** Me equatorial → minimal 1,3-diaxial strain, most stable - **(III)** Me axial, H axial → severe 1,3-diaxial strain (similar to I) - **(IV)** Me equatorial-like position → minimal strain **Strain Comparison:** 1. **(III) is most stable** — methyl group is in equatorial/favorable position with minimal repulsion 2. **(I) and (II) are approximately equal** — both have significant 1,3-diaxial interactions between axial Me and axial H atoms. The ring geometry creates comparable steric effects in both. 3. **(IV) is least stable** — the bridged structure creates greater ring strain and angular strain despite favorable Me positioning ## Correct Order (Decreasing Stability): $$\boxed{\text{(III) > \text{(I)} \approx \text{(II)} > \text{(IV)}}$$ **Answer: (D)** The key insight is that 1,3-diaxial strain makes (I) and (II) roughly equivalent, while (IV)'s bridged geometry introduces excessive ring strain, making it least stable.