See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Optical Activity Analysis **Optical activity requires a chiral center (stereocenter)** — a carbon bonded to four different groups. **Analyzing each structure:** **(1)** Four-membered ring with two $OH$ groups on same carbon - This carbon has two identical $OH$ groups - Not a chiral center → **Optically inactive** **(2)** Five-membered ring with $SH$ and $Br$ on same carbon - This carbon bonded to: ring carbon, $SH$, $Br$, and $H$ (four different groups) - **Chiral center present** → **Optically active** ✓ **(3)** Five-membered ring with $SH$ and $Br$ on same carbon - Same as (2) — has four different groups - **Chiral center present** → **Optically active** ✓ **(4)** Six-membered ring with $CH_3$ and $H$ on same carbon - This carbon bonded to: two ring carbons (same group counted twice), $CH_3$, and $H$ - Does not have four different groups - **Not optically active** --- **Answer: Option (2)** has a clear chiral center with four distinct substituents ($-SH$, $-Br$, $-H$, and the ring), making it optically active.