I know when cracking usually an alkane and an alkene is produced,
Agreed
but why when cracking hexane the equation
C6H14 → C3H6 + C3H8
and not C6H14 → C4H8 + C2+H6
because both are an alkane and an alkene.
Is "C2" an alkane or alkene ?
Is "H6" an alkane or alkene ?
But separately, I have read that cracking produces a "variety" of
hydrocarbon (emphasis intended) products . So going back to your first equation
C
6H
14 → C
3H
6 + C
3H
8I'm not sure that C
3H
6 + C
3H
8 will be the
only products - which is where you came in.
Now ... going back to what you wrote I guess you made a slight slip and meant
C
6H
14 → C
4H
8 + C
2H
6which balances OK.
However, it might be the case that the energy of the various paths favour the production of certain products rather than others, or that there might be "rules" that guide where the splitting takes places - but I haven't come across them.
I too will be interested to find out if there is a "definitive" answer to this.
Clive