See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Step 1 - Concept: Dipole moment arises from asymmetric charge distribution. Aromatic systems with polar functional groups and charge delocalization can have significant dipole moments. Step 2 - Analyze options (a) and (b): Benzene is a symmetric, nonpolar molecule with zero dipole moment. Naphthalene is also symmetric and nonpolar with zero dipole moment. Step 3 - Analyze options (c) and (d): Both structures appear to be cyclopropenone derivatives bearing two phenyl groups. Option (c) is 2,3-diphenylcyclopropenone. Cyclopropenone itself has an exceptionally large dipole moment (~4.39 D) because the cyclopropenyl cation (2π aromatic system) stabilizes a zwitterionic resonance structure C3H2=O <-> [C3H2]+(aromatic) [O]-. This aromatic stabilization of the positive charge on the three-membered ring greatly enhances the C=O dipole. Step 4 - Why (c) > (d): Option (c) is 2,3-diphenylcyclopropenone, where the two phenyl groups further stabilize the cyclopropenyl cation through resonance, maximizing the contribution of the zwitterionic form and thus maximizing the dipole moment. Option (d) appears structurally similar but the connectivity or substitution pattern provides less effective resonance stabilization compared to (c). Step 5 - Why (c) has maximum dipole moment: The cyclopropenone ring in (c) benefits from 2π Hückel aromaticity of the cyclopropenyl cation in its resonance structure, and the two flanking phenyl groups further stabilize this cationic character, making the zwitterionic resonance structure dominant and producing an exceptionally large dipole moment exceeding typical carbonyl compounds. Therefore, the correct answer is C.