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Chemistry · PYQ NEET UG 2022
हिन्दीWhich of the following compounds is NOT an aromatic compound?
Correct answer · Option 2
CH₂
Explanation
An aromatic compound must be cyclic, planar, completely conjugated, and follow Hückel's rule (\( 4n + 2 \) \( \pi \)-electrons).
Option (2) represents cycloheptatriene, which contains an \( sp^3 \)-hybridized \( -\text{CH}_2- \) group in the ring, making it non-planar and disrupting continuous cyclic delocalization of electrons. Therefore, it is non-aromatic.
The other options are aromatic: Option (1) is the cyclopentadienyl anion (\( 6\pi \)-electrons), Option (3) is benzene (\( 6\pi \)-electrons), and Option (4) is the tropylium cation (\( 6\pi \)-electrons).
Option (2) represents cycloheptatriene, which contains an \( sp^3 \)-hybridized \( -\text{CH}_2- \) group in the ring, making it non-planar and disrupting continuous cyclic delocalization of electrons. Therefore, it is non-aromatic.
The other options are aromatic: Option (1) is the cyclopentadienyl anion (\( 6\pi \)-electrons), Option (3) is benzene (\( 6\pi \)-electrons), and Option (4) is the tropylium cation (\( 6\pi \)-electrons).
