Q. Among the following, the aromatic compound is
Haryana PMTHaryana PMT 2011
Solution:
According to Huckels rule for aromaticity, the aromatic molecule must be planar, cyclic system having delocalised $ (4n+2) $ $ \pi $ electrons
where, $n$ is an integer, i.e., $0, 1, 2, 3, ....$
Thus, aromatic compounds must have $2, 6, 10$ or $ 14\pi $ -electrons. Cyclopropenyl cation
has $ 2\pi $ -electrons $ (n=0) $ , hence it is aromatic compound.
