85. A weighed sample of H2C2O4 * 2H2O 2.00 g dissolved in 300 cm3 for titration of 25.00 cm3 of this solution, 24.50 cm3 of a KMnO4 solution with C (1 / 5KMnO4) = 0.1064 mol / dm3 is consumed. What percentage of H2C2O4 * 2H2O does the sample contain?