See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Identifying the Aromatic Compound **Step 1: Apply Hückel's Rule** For a compound to be aromatic, it must have $(4n + 2)$ π electrons, where $n = 0, 1, 2, ...$ **Step 2: Analyze Each Option** **(A) Cyclopropenyl cation** ($C_3H_3^+$) - 3-membered ring with one positive charge - π electrons = 2 (from the double bond, excluding the carbocation) - Actually has **2 π electrons** = $4(0) + 2$ ✓ - Satisfies Hückel's rule → **AROMATIC** **(B) Cyclopentadienyl cation** ($C_5H_5^+$) - 5-membered ring with one positive charge - π electrons = 4 (two double bonds) - Does not satisfy $4n + 2$ → NOT aromatic **(C) Cyclobutadiene** ($C_4H_4$) - 4-membered ring - π electrons = 4 = $4(1)$ → NOT aromatic (antiaromatic) **(D) Cyclopropenyl anion** ($C_3H_3^-$) - 3-membered ring with one negative charge - π electrons = 4 → Does not satisfy $4n + 2$ → NOT aromatic **Answer: (A)** The cyclopropenyl **cation** is aromatic because it has exactly 2 π electrons, satisfying Hückel's rule with $n = 0$.