See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Conformer Stability Analysis **Step 1: Identify the structure type** All structures show cyclohexane derivatives with substituents in axial/equatorial positions. Stability depends on minimizing steric clashes (1,3-diaxial interactions). **Step 2: Count axial substituents for each conformer** **(A):** $HO$, $CH_3$, $OH$, $CH_3$ — 4 bulky groups in axial positions - Multiple 1,3-diaxial interactions between $OH$ and $CH_3$ groups → **High strain** **(B):** Two $CH_3$ groups and two $OH$ groups in axial positions - 4 axial substituents → **High strain** **(C):** Two $CH_3$ groups and two $OH$ groups in axial positions - 4 axial substituents → **High strain** **(D):** Only $H$ atoms in axial positions; $OH$ and $CH_3$ are equatorial - **All bulky groups occupy equatorial positions** → Minimal steric interference **Step 3: Apply conformational principles** The most stable cyclohexane conformation has: - Bulky/polar groups in **equatorial positions** (pseudo-axial space is larger) - Hydrogen atoms in **axial positions** **Answer: (D)** is least stable is incorrect — **(D) is MOST stable** because all substituents occupy the lower-strain equatorial positions, avoiding 1,3-diaxial interactions entirely. *[Note: If the question asks for "least stable," the answer would be **(A)** or **(B)** due to maximum axial crowding.]*