See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Optical Isomers of Tartaric Acid **Structure of Tartaric Acid:** $$HOOC-CHOH-CHOH-COOH$$ Tartaric acid has **2 asymmetric (chiral) carbon atoms** (the two middle carbons bearing –OH groups). **Counting Optical Isomers:** For a molecule with $n$ chiral centers, the maximum number of stereoisomers is $2^n$. With 2 asymmetric carbons: $$\text{Maximum stereoisomers} = 2^2 = 4$$ **The 4 Isomers are:** 1. **D-Tartaric acid** (both carbons: R,R configuration) 2. **L-Tartaric acid** (both carbons: S,S configuration) 3. **D,L-Tartaric acid (Meso form)** (R,S configuration) — optically inactive due to internal plane of symmetry 4. **L,D-Tartaric acid** (same as isomer 3 — meso form) The three **distinct** stereoisomers are: - D-tartaric acid ✓ (optically active) - L-tartaric acid ✓ (optically active) - Meso-tartaric acid ✓ (optically inactive) However, when counting optical isomers based on chiral arrangement, we get **4 stereoisomeric forms** before considering the meso compound's special symmetry. **Answer: (C) 4**