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Assertion (A) The compound tetraene has ...

Assertion (A) The compound tetraene has the following structural formul.

It is cyclic and has conjugated `8pi`-electron system but it is not an aromatic compound.
Reason (R ) `(4n + 2)pi` electrons rule does not hold good and ring is not planar.

A

Both A and B are correct and R is the correct explanation of A

B

Both A and R are not correct

C

Both A and R are not correct

D

A is not correct but R is correct

Text Solution

Verified by Experts

The correct Answer is:
a
Both assertion and reason are correct and reason is the correct explanation of assertion .
According to Huckel rule Aromaticity is shown by compounds possessing following characteristics
(i) compound must be planar and cycilc
(ii) Complete delocalisation of `pi` electrons in the ring
(iii) Presence of conjugated `(4n+2) pi` electrons in the ring where n is an integer (n=0, 1, 2,...) cyclo octatetraeng (given ) has a tub like structure . It loses planaritt\y. No. of `pie^(-)` delocalised = 8 and n is not integer. Hence, cyclotatetraene is a non-aromatic compound.
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Knowledge Check

  • This section contains Assertion (A) and Reason® type questions each question has choices (1)(2)(3)(4) out of which only one is correct Assertion: The compound cyclooctane has the following structural formula it is cyclic and has conjugated 8pi electron system but it is not an aromatic compound Reason: (4n+2)pi electrons rule does not hold good and ring is not planar

    A
    Both A and R are correct ,R is the correct explanation of A
    B
    Both A and R are correct,R is not the correct explanation of A
    C
    A is correct ,R is incorrect
    D
    R is correct,A is incorrect

  • A compound, PQ_2 has the following arrangement of electrons : The elements P and Q are respectively:

    A
    N,Cl
    B
    Cl,S
    C
    O,F
    D
    Na,F

  • Assertion : Pyrrole is an aromatic heterocyclic compound . Reason:It has a cyclic , delocalised 6pi electrons

    A
    If both assertion and reason are true and the reason is the correct explanation of the assertion
    B
    If both assertion and reason are true but reason is not the correct explanation of the assertion
    C
    if assertion is true but reason is false
    D
    If assertion and reason both are false