Exams › JEE Main › Chemistry

Two statements are given. Assertion A: [6]Annulene, [8]Annulene and cis-[10]Annulene are aromatic, non-aromatic and aromatic respectively. Reason R: One of the conditions for aromaticity is that the ring be planar. Select the most appropriate response.

1. Both A and R are correct and R is the correct explanation of A.
2. Both A and R are correct but R is NOT the correct explanation of A.
3. A is correct but R is not correct.
4. A is not correct but R is correct.

Correct answer: Both A and R are correct and R is the correct explanation of A.

Solution

[6]Annulene = benzene: planar, 6 pi e (4n+2, n=1), aromatic. [8]Annulene = cyclooctatetraene: 8 pi e (4n) and non-planar tub shape, so non-aromatic. cis-[10]Annulene: 10 pi e (4n+2, n=2) and the cis isomer can be planar, so aromatic. Thus A is correct. Planarity is indeed a requirement and it is exactly the property explaining why [8]annulene fails while the others succeed, so R correctly explains A.

Related JEE Main Chemistry questions

• Arrange the following carbanions in decreasing order of basicity: (A) CH3CH2−, (B) CH2=CH−, and (C) HC≡C−.
• In acid-catalyzed hydration of alkenes, all alkenes except ethene generally give rise to which type of alcohol product?
• Which of the following organic compounds has the same hybridization as the carbon atom in its combustion product, CO2?
• What is formed when CH3MgX reacts with CH3C≡CH?
• Which of the following reagent sets can be used to convert propene into 1-propanol?
• When ethyne (H–C≡CH) is treated first with (1) NaNH2 in liquid NH3 and then with (2) CH3CH2Br, the product X is formed. If X is again subjected to the same two-step sequence, the product Y obtained is:

⚔️ Practice JEE Main Chemistry free + battle 1v1 →