A 1.762 g sample of impure H2C2O4 (MW =90.04) was dissolved in water and the impurities removed by filtration. 50.00 mL of .01028 M NaOH was added to the filtrate, this being in excess of the amount needed to neutralize both hydrogens of the H2C2O4. The excess NaOH required 12.62 mL of 0.1251M HCl to reach the equivalence point. What was the weight % of H2C2O4 in the sample.