See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Resonance Energy Order **Key Principle:** Resonance energy increases with: - Greater extent of conjugation/aromaticity - More stable resonance structures - Better orbital overlap in conjugated systems --- ## Evaluation of Each Option: **(a) Tetralin < Naphthalene** ✓ **CORRECT** - Naphthalene: fully aromatic, two fused benzene rings with extended conjugation - Tetralin: one benzene ring + one saturated ring; less aromatic character - Naphthalene has higher resonance energy **(b) N-methylpyrrole > conjugated diene with $NHCH_3$** ✓ **CORRECT** - N-methylpyrrole: aromatic (5-membered ring with $\pi$ electrons) - Right compound: simple conjugated diene without aromaticity - Aromatic compound has higher resonance energy **(c) Anthracene < 9,10-dihydroanthracene** ✗ **INCORRECT** - **Anthracene:** fully aromatic tricyclic system with significant resonance stabilization - **9,10-dihydroanthracene:** center ring is saturated (lost aromaticity at middle ring) - Anthracene should have **HIGHER** resonance energy than its saturated analog - The inequality is **reversed** **(d) 2H-pyran > pyran** ✓ **CORRECT** - Pyran (2H-pyran): saturated center, less aromatic - Pyran (aromatic): more conjugated - Order is correct (though subtle) --- **Answer: (c) is incorrect** because anthracene, being fully aromatic with extended conjugation, has greater resonance energy than its partially saturated derivative.