41. Solving a chemistry problem

4. Cranberries and lingonberries can be stored fresh for a very long time without sugar, as this is facilitated by the presence of a preservative in them.
1) Set the molecular formula of this natural preservative if the mass fractions of the elements in it are: carbon - 68.85%, hydrogen - 4.92%, oxygen - 26.23%. Name it.
2) Write the reaction equation for its preparation by oxidation of potassium permanganate in an acidic medium
3) How is the preservative used?