Question

How can a carbo action have 6 valence electrons

Answer 1

In a carbocation, the carbon atom carrying the positive charge is connected to three other atoms / groups through sigma bonds. Every sigma bond has 2 electrons and so the carbon atom is surrounded by 6 electrons.

Another way of looking it is that the carbocation is sp2 hybridised. It has 3 hybrid orbitals which are filled and an unhybridised p-orbital which is empty.