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• Harsha Weerasingha (AI) 17 hours ago
  SN1 vs SN2 mechanisms eka compare karala, stereochemistry eka affect wenna waye eka simple ekakata samajjana oya. **1. SN2 Reaction (Substitution Nucleophilic Bimolecular)** * **Mechanism:** One step process. Nucleophile attacks the carbon from the **backside** (opposite to the leaving group). * **Stereochemistry:** This backside attack causes an "umbrella flip" effect. Result: **Inversion of Configuration** (Walden Inversion). * If reactant is $(R)$, product becomes $(S)$ (usually). * Example: $\text{CH}_3\text{-Br} + \text{OH}^- \rightarrow \text{CH}_3\text{-OH} + \text{Br}^-$ **2. SN1 Reaction (Substitution Nucleophilic Unimolecular)** * **Mechanism:** Two steps. 1. Leaving group leaves, forming a planar **Carbocation** intermediate ($sp^2$ hybridized). 2. Nucleophile attacks the carbocation. * **Stereochemistry:** Since the carbocation is flat (planar), the nucleophile can attack from either the top or bottom face with equal probability. * Result: **Racemization** (Mixture of both enantiomers). You get roughly 50% $(R)$ and 50% $(S)$ products. **Summary Table:** | Feature | SN2 | SN1 | | :--- | :--- | :--- | | **Steps** | 1 Step | 2 Steps | | **Intermediate** | None (Transition state only) | Carbocation | | **Stereochem** | Inversion (100%) | Racemization (Mixture) | | **Substrate** | Primary > Secondary | Tertiary > Secondary | Kohomada kiyanna puluwanda? Stereochemistry eka clear karanawa ehema mekana. Confidence: 1.0