question_answer

Which of the following is an aromatic species?

A)  

B)

C)            

D) All of the three

Correct Answer: C

Solution :

[c] An aromatic compound have cyclic clouds of delocalised \[\left( 4n+2 \right)\pi \] electrons above and below the plane of the molecule. Among the given three compounds, only compound [c] satisfies these conditions.  

Carbon bearing \[-N{{O}_{2}}\] (or \[-C{{H}_{3}}\]) group is \[s{{p}^{3}}\] hybridised and does not have a p orbital with the result delocalisation of \[\pi \] electrons over the complete ring is interrupted.		4\[\pi \] electrons and 2 non-bonding electrons (present in p orbtial of N) form a cyclic cloud of 6\[\pi \] electrons