See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Identifying the Meso-Compound A **meso-compound** contains chiral centers but is achiral overall due to an internal plane of symmetry. ## Analysis of Each Option: **Option (1):** Tartaric acid derivative - Has two chiral centers with opposite configurations - No internal plane of symmetry - NOT meso **Option (2):** 2,3-butanediol with $CH_3$ groups - Has two chiral centers at middle carbons - Configuration: $(R,S)$ or $(S,R)$ reading the wedge-dash structure - **Contains an internal plane of symmetry** perpendicular to the C-C bond - The left chiral center is mirror image of the right - **This IS a meso-compound** ✓ **Option (3):** Lactic acid derivative - Both $OH$ groups on same side (both H pointing up) - Both chiral centers have same stereochemistry - No plane of symmetry - NOT meso **Option (4):** 1,3-dichloropropanediol - Chiral center only at C-2 (C-1 and C-3 are achiral) - Only one chiral center, so cannot be meso - NOT meso ## Answer: **(2)** Option (2) is the meso-compound because it possesses two chiral centers with opposite configurations and an internal plane of symmetry, making it optically inactive despite containing stereogenic centers.