Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R .…

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A:6 Annulene. 8 Annulene and cis -10 Annulene, are respectively aromatic, not-aromatic and aromatic.

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Reason R: Planarity is one of the requirements of aromatic systems.

In the light of the above statements, choose the most appropriate answer from the options given below.

  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.

Solution

In 10-Annulene - the hydrogen atoms in the 1 and 6 position interfere with each other and force the molecule out of planarity

If this annulene with five cis double bonds were planar, each internal angle would be 144°. Since a normal double bond has bond angle of 120°, this would be from ideal. This compound can be made but it does not adopt a planar conformation and therefore is not aromatic even though it has ten π electrons.

Asked in: JEE Main 2022 (27 Jul Shift 1)

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