18. which of the following is aromatic. (6) (singlet carber) (d) (singlet carbene)

See Sanu singlet carbene are sp2 hybridized.

lone pair reside in sp2 hybridized carbon.

So singlet carbene has 1 empty p orbital.

This p orbital is used for delocalization

Hence continuous delocalization is maintained.

Molecule is also planar

it satisfy 4n+2 rule.

So all the condition of Huckle is satisfied

So b is aromatic.

If still you don't get anything then please ask

sir,for singlet carbene we have to proceed like this only

Yes Sanu.

Triplet carbene is sp hybridized.

So it has 2 'p' orbital but both are singly occupied

thank u sir

here carbene is not take part in the conjunction. so onlt 3 pi bonds involved in resonance make it aromatic

check it for reference

got it?

thank u sir

here special conjugation occurs in case of singlet carbene

lone pair is not in conjugation rather double bond-empty p orbital and double bond conjugation occurs

a,c, and d are anti aromatic

In singlet carbene case the lone pair resides in sp2 hybridised orbital and p orbital is empty ...so conjugation between double bond empty p orbital and double bond occurs

got this??

check this sanu👇

check this👆

please ask if you have any doubt😊

sir,for singlet carbene we have to proceed like this

yes,sanu here conjugation is complete ...it is special type of conjugation...so you do like this for aromaticity

ok sir thanku

you are welcome Sanu