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.

Options

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

Answer

a

Explanation

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.