the free energy for the oxidation of glucose to co2 and water is -686 kcal/mol and the free energy for the reduction of nad to nadh is 53 kcal/mol. why are only two molecules of nadh formed during glycolysis when it appears that as many as a dozen could be formed? the free energy for the oxidation of glucose to co2 and water is -686 kcal/mol and the free energy for the reduction of nad to nadh is 53 kcal/mol. why are only two molecules of nadh formed during glycolysis when it appears that as many as a dozen could be formed? there is no co2 or water produced as products of glycolysis. most of the free energy available from the oxidation of glucose is used in the production of atp in glycolysis. glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat. most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.