Why can't you separate carbon hydrogen and oxygen from sugar?

Answer 1

It is not impossible to separate the carbon, hydrogen, and oxygen from the sugar molecule, but in practice you would be very unlikely to do that since there are much easier and less expensive sources for all 3 of those elements. Coal is a source of carbon, air contains oxygen, and hydrogen can be obtained by the electrolysis of water (or by a number of other methods).

Answer 2

Sugar is a complex molecule made up of carbon, hydrogen, and oxygen atoms bonded together in a specific arrangement. Separating these elements requires breaking these chemical bonds, which typically requires a significant amount of energy. Additionally, the process of breaking down sugar into its individual elements is not easily achievable in a practical or scalable manner.