See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Aromatic Intermediate Identification **Key Concept:** An aromatic intermediate must have a **cyclic, planar structure with continuous π-electron delocalization** following Hückel's rule ($4n+2$ π electrons). **Analysis of each option:** **(A) Carbene** — Not aromatic. Carbene ($:C$) is a highly reactive species with only 2 electrons and no cyclic structure. **(B) Cyclohexadienyl radical** — Not aromatic. The structure shown has a radical (•) on the sp² carbon, disrupting the continuous π-system. It has 5 π electrons (odd number), making it antiaromatic and unstable. **(C) Benzyne** — **Aromatic intermediate.** Despite having a triple bond (acetylenic character) in the six-membered ring, benzyne maintains: - Cyclic, planar structure - 6 π electrons in the delocalized system - Follows Hückel's rule: $4n+2$ where $n=1$ → 6 electrons ✓ - Exists as a true intermediate in nucleophilic aromatic substitution reactions **(D) Cyclobutadiene radical cation** — Not aromatic. The four-membered ring with a radical has an odd number of π electrons and is antiaromatic (4 = $4n$ where $n=1$). **Answer: (C) Benzyne** is the only structure with continuous aromaticity and stability to function as an actual reaction intermediate.