(ii)
(iii) 
(iv) 
Answer:
Compound (i) contains\[(4\,n+2)\pi
\] electrons where \[n=2\], i.e., it contains \[5\times 2=10\,\pi \]-electrons
and hence according to Huckel rule, it is aromatic.
Compound (iii) is also aromatic since it
contains two benzene rings each one of which contains \[(4n+2)\pi -\]electrons
with n = 1, i.e.,\[3\times 2=6\] electrons.
Compound (ii) is a \[4\,n\,\pi
\,(n=1)\] electron system and hence is an antiaromatic compound.
Although compound (iv) contains \[6\,\pi
\]-electrons, i.e.,\[(4\,n\,+2)\pi \] electrons with n = 1, yet the system is
not completely conjugated due to the presence of a \[s{{p}^{3}}\]-hybridized
carbon. In other words, this compound is not planar and hence is not aromatic.
You need to login to perform this action.
You will be redirected in
3 sec
