See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Stereoisomers of 2,3-Dibromobutane **Step 1: Identify the structure** 2,3-Dibromobutane has the structure: $CH_3-CHBr-CHBr-CH_3$ Chiral centers are at C-2 and C-3 (both bearing Br atoms). **Step 2: Determine possible stereoisomers** With 2 chiral centers, the maximum possible stereoisomers = $2^2 = 4$ Theoretically possible: - (2R, 3R) - (2S, 3S) - (2R, 3S) - (2S, 3R) **Step 3: Check for meso compound** The molecule has a plane of symmetry when we consider (2R, 3S) and (2S, 3R) configurations—these are actually the **same compound** (meso form), not enantiomers. The meso form is achiral despite having chiral centers because internal symmetry makes it superimposable on its mirror image. **Step 4: Count actual stereoisomers** - (2R, 3R) — one enantiomer - (2S, 3S) — enantiomer of the above - (2R, 3S) = (2S, 3R) — meso compound (single achiral form) **Total = 3 distinct stereoisomers** --- **Note:** The given answer (A) 2 appears incorrect. The correct answer should be **(B) 3** (two enantiomers + 1 meso compound).