See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Solution: Basic Strength Order of Aromatic Amines **Key Principle:** Basic strength depends on electron density at the nitrogen atom. More electron density → stronger base. **Analysis of each compound:** **(I) Diphenylamine** ($C_6H_5-NH-C_6H_5$) - Two aromatic rings directly attached to N - Both rings withdraw electron density via resonance - Lowest basicity **(II) N-methylaniline** ($C_6H_5-NH-CH_3$) - One aromatic ring (withdraws electrons) - One alkyl group (donates electrons) - Intermediate basicity **(III) Dimethylamine** ($(CH_3)_2NH$) - Two alkyl groups (both donate electrons) - No aromatic ring to withdraw electrons - Highest basicity **(IV) Aniline** ($C_6H_5-NH_2$) - One aromatic ring (withdraws electrons via resonance) - Stronger effect than one ring + one alkyl (II) - But weaker than saturated dimethylamine (III) **Resonance Effect (Primary Factor):** Aromatic rings delocalize the lone pair on N through resonance, reducing electron density: $$C_6H_5-N \rightleftharpoons C_6H_5-\overset{+}{N}=\text{(aromatic carbons)}$$ **Correct Order:** (I) < (IV) < (II) < (III) **Answer: (A)**