There are two possible isomers for the molecular formula C3H8O:1. Propan-1-ol also known as 1-propanol or n-propyl alcohol : CH3CH2CH2OH2. Propan-2-ol also known as 2-propanol or isopropyl alcohol : CH3CH OH CH3Both of these compounds are alcohols with three carbon atoms and one hydroxyl group. The difference lies in the position of the hydroxyl group on the carbon chain.