Question
Which of the following will exhibit aromatic character?
Which of the following will exhibit aromatic character?
A.
I, III
B.
III, IV
C.
II, IV
D.
II, III
Answer :
II, IV
Solution :
Since in azulene (IV) two rings share a double bond, therefore, two electrons of this double bond can be counted towards each. As a result, each ring has \[6\,\pi \] - electrons and hence azulene is aromatic. Pyrrole (II), is aromatic because it contains \[6\pi \] - electrons ( four from the two double bonds + one lone pair of electrons on the $$N$$ atom ).
Since in azulene (IV) two rings share a double bond, therefore, two electrons of this double bond can be counted towards each. As a result, each ring has \[6\,\pi \] - electrons and hence azulene is aromatic. Pyrrole (II), is aromatic because it contains \[6\pi \] - electrons ( four from the two double bonds + one lone pair of electrons on the $$N$$ atom ).