JEE Main 2022 · 28 Jun · Shift 1 · Chemistry Q72

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ChemistrySingle correct+4 / -1Question 72 of 90

Which of the following structures are aromatic in nature ?

Four structures: A cyclopentadienyl anion; B cycloheptatrienyl (tropylium) cation; C 4a,8a-dihydronaphthalene (two fused six-membered rings, two C=C in each ring, sp3 ring-fusion carbons); D cycloheptatrienyl anion.

A, B, C and D

Only A and B

Only A and C

Only B, C and D

Answer and worked solution

Official answer: B

A cyclopentadienyl anion: 6π, planar, aromatic. B tropylium cation: 6π, aromatic. C has sp³ ring-fusion carbons (4a,8a-dihydronaphthalene), so it is not fully conjugated. D cycloheptatrienyl anion: 8π, not aromatic.

(B)

Topics:Aromaticity

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JEE Main 2022 · 28 Jun · Shift 1, Chemistry question 72