The formula of ethane is C2H6 while the formula of ethanol is C2H6O.
As we can notice, they are almost common in the structure with the exception of the oxygen atom that is found in the ethanol.
Ethane structure has two carbon atoms attached together and each of these atoms is attached to another three hydrogen atoms.
As for ethanol, it has the same structure except that one of the hydrogen atoms attached to a carbon is replaced by O-H.
