See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Understanding Nucleophiles **Definition**: A nucleophile is a species that donates an electron pair to an electrophile during a chemical reaction. **Step-by-step analysis**: 1. **Option (1) - Lone pair containing** ✓ - Nucleophiles must possess at least one lone pair of electrons to donate - This lone pair attacks electron-deficient centers (electrophiles) - Examples: $OH^-$, $NH_3$, $:C\equiv C:^{2-}$ 2. **Option (2) - Electron deficient** ✗ - Electron-deficient species are **electrophiles**, not nucleophiles - They accept electrons, not donate them - Example: $BF_3$, $AlCl_3$ 3. **Option (3) - Lewis acid** ✗ - Lewis acids accept electron pairs (electrophiles) - Nucleophiles are Lewis bases (electron pair donors) - These are opposite concepts 4. **Option (4) - Positive charge** ✗ - Nucleophiles are typically negatively charged or neutral with lone pairs - Positive species attract electrons and are electrophilic - Example: positive charge repels nucleophilic attack **Conclusion**: A nucleophile **must have a lone pair** to donate electrons. This is the fundamental requirement for nucleophilic reactivity. **Answer: (1) Lone pair containing**