I really need help I am stuck! PLEASE

Question

The balanced equation for the titration of oxalic acid with potassium permanganate is:

2 KMnO₄ + 5 H₂C₂O₄ + 3 H₂SO₄ → 2 MnOS₄ + 10 CO₂ + K₂SO₄ + 8 H₂O

What is the concentration of a 25 mL oxalic acid solution that requires 21.1 mL of a 0.0203 M KMnO4 solution to reach the endpoint of the titration? (4 decimal places)

Answer 1

You need to use mole-matching here. 21.1 mL of a .0203 M solution of KMnO4 yields (.0211*.0203) moles or .000428 moles of potassium permanganate.

The balanced equations says that 2 moles of potassium permanganate needs 5 moles of oxalic acid to titrate to the endpoint. So we need 5*.000428/2 = 0.00107 moles. of H2C2O4

We want to find the concentration of oxalic acid where 0.00107 = M*.025L .

So M = .00107/,025 = 0.0428 M/L