See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Analysis of 2,3-Dichlorobutane Isomerism **Structure of 2,3-dichlorobutane:** $$CH_3-CHCl-CHCl-CH_3$$ The two chiral centers are at C2 and C3 (both bearing Cl atoms). --- ## Why Option (A) - Conformational Isomerism: ✓ - The single bonds allow **free rotation** around the $C-C$ bonds - Different spatial arrangements (eclipsed, staggered, gauche) exist without breaking bonds - These are **rapidly interconvertible** at room temperature - Example: Rotation around the $C2-C3$ bond creates different conformers --- ## Why Option (C) - Optical Isomerism: ✓ - Both C2 and C3 are **chiral centers** (4 different groups attached) - The compound exists as **stereoisomers** (enantiomers and diastereomers): - $(2R, 3R)$ and $(2S, 3S)$ — enantiomers - $(2R, 3S)$ and $(2S, 3R)$ — diastereomers (meso form) - These isomers are **non-superimposable** and show optical activity (rotate plane of polarized light) --- ## Why NOT (B) & (D): **(B) Geometrical:** Requires restricted rotation (double bonds) — not present here **(D) Tautomerism:** Requires migration of atoms/bonds — doesn't apply **Answer: (A) and (C)**