Which of the following is aromatic carbocation?
[Step 1]:
In option (1), two carbons are SP3 and non-planar.
Non conjugated and not obeys Huckel’s rule
[Step 2]:
In option (2) all three carbons are SP2 planar cyclic, conjugated and contains 2πe- i.e, obeys Huckel’s rule. Therefore it is an aromatic compound
[Step 3]:
In option (3) one carbon is SP3 and non-planar
[Step 4]:
In option (4) , number of πe- are 4 i.e, not obeys Huckel’s rule.