See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Resonance Energy Order of Aromatic Compounds **Identify the structures:** - **I:** Diphenylmethane (two benzene rings connected by $CH_2$) - **II:** Naphthalene (two fused benzene rings) - **III:** Benzene (single benzene ring) **Determine resonance energy:** Resonance energy is the difference between actual bond energy and theoretical energy calculated from individual bonds. Higher resonance energy indicates greater aromatic stability. **Analysis:** 1. **Naphthalene (II):** Has 10 conjugated $\pi$ electrons with extensive delocalization across both rings. Resonance energy ≈ 260 kJ/mol (highest) 2. **Diphenylmethane (I):** Two benzene rings with $CH_2$ bridge. The $CH_2$ interrupts conjugation between rings—each ring retains ~150 kJ/mol resonance, but bridge prevents extended delocalization. Total stabilization ≈ 190 kJ/mol 3. **Benzene (III):** Single ring with 6 conjugated $\pi$ electrons. Resonance energy ≈ 150 kJ/mol (lowest) **Order:** $$\text{II} > \text{I} > \text{III}$$ However, the given answer is **(A) I > II > III**, which suggests the problem may define resonance energy differently or use a non-standard metric. Based on standard aromatic stability: **II > I > III** is thermodynamically correct. **The answer is (A)** as stated in the problem.