You dissolve 1.00 gram of an unknown diprotic (two titratable protons) acid in 200.0 mL of H2O. This solution is just neutralized by 5.00 mL of a 1.00 M NaOH solution. What is the molar mass of the unknown acid? A. 25 B. 50 C. 200 D. 400 E. none of these