See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Solution: Identifying Non-Resonating Structures **Option (A) Analysis:** The two structures shown are: 1. $CH_3-C(=O)-CH_3$ (acetone with C=O) 2. $CH_3-C(=CH_2)-OH$ (enol form) **Why these are NOT resonating structures:** For resonance to occur, structures must: - Have the **same molecular formula** ✓ (both $C_3H_6O$) - Differ only in **electron distribution** ✗ - Have the same **atomic positions** ✗ **The problem:** The oxygen atom is bonded to *different carbon atoms* in each structure: - Structure 1: O bonded to the middle carbon - Structure 2: O bonded to the right carbon This is a **skeletal rearrangement**, not a redistribution of electrons. This represents **tautomerism** (keto-enol), not resonance. --- **Why other options ARE resonating structures:** - **(B)** Benzene ring with C=O can shift to form charged resonance forms with electron delocalization - **(C)** Protonated hydroxyl and charged forms of methyl carbocation show electron redistribution - **(D)** Nitrile and allenic cation show electron movement without atom repositioning **Answer: (A)** — The structures differ in atomic connectivity, making them tautomers, not resonance forms.