1. Compare and contrast the terms "primary standard" and "secondary standard." pure, stable, high molemmber weight no hydration, no water. Primary standard Secondary standard - prepared in the lab for a specific analysis. 2. Calculate the mass of oxalic acid dihydrate (C,H,O, 2H,O) needed to prepare 500.0 mL. of 0.2500 M oxalic acid solution. 0.2500 M sox . During a titration, a student used 31.92 mL of a NaOH solution to neutralize 30.0 mL of 0.2488 M oxalic acid solution. (Note: Oxalic acid is diprotic!) a. Write the balanced equation for the neutralization reaction. (See question 2 for the formula of oxalic acid.) b. How many moles of oxalic acid were present in the sample?