Oxalic acid (C2H2O4) is a diprotic acid. A student was testing a lab sample that contained some diprotic acid. The student measured out 2.50 g of the sample and added it to a 250 mL volumetric flask. The student then added water to make it up to 250 mL. The student took out 25 mL aliquot into a conical flask. This was then titrated with potassium hydroxide solution with a concentration of 1.20 M. The following titres were obtained: 15.25 mL, 15.10 mL, 15.00 mL and 15.02 mL. a. Calculate the concentration of oxalic acid in the 25 mL aliquot.

b. Calculate the concentration of oxalic acid in the 250 mL volumetric flask.