You dissolve 1.05 grams of an unknown diprotic 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?

Answer 1

H2A + 2NaOH ==> 2H2O + Na2A

mols NaOH = M x L = ?
mols H2A = 1/2 that (from the coefficients in the equation).
mols H2A = grams H2A/molar mass H2A. You have grams and mols, solve for molar mass.

Answer 2

420