See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Nucleophilicity Analysis **Nucleophilicity** is the ability of a species to donate electron density to an electrophilic center. Key factors: - **Charge density**: More negative = more nucleophilic - **Atom size**: Larger atoms can better stabilize negative charge - **Basicity**: In aprotic solvents, basicity correlates with nucleophilicity **Evaluating each option:** | Species | Character | Nucleophilicity | |---------|-----------|-----------------| | $F^-$ | Anion, small atom | Moderate (high charge density, but small) | | $OH^-$ | Anion, electronegative | Moderate (oxygen is electronegative) | | $CH_3^-$ | **Carbanion** | **Very high** ✓ | | $NH_2^-$ | Anion, small atom | Moderate | **Why $CH_3^-$ is highest:** The methyl anion is a **carbanion** with a lone pair on carbon. Carbon is: - **Large enough** to accommodate negative charge better than F or N - **Less electronegative** than O or F, so it **doesn't withdraw** electron density - **Highly basic** → in aprotic media, this directly translates to high nucleophilicity The negative charge is loosely held on carbon, making electrons readily available for nucleophilic attack. **Answer: (C) $CH_3^-$**