Question

What is the molarity of an unknown H₂C₂O₄ solution if 10.0 mL of the H₂C₂O₄ solution required 21.3 mL of 0.025 M KMnO₄ solution to obtain a stoichometric endpoint?

Please show work so that I can understand how to solve problem. Thanks!!!

Answer 1

Solution :-

Balanced reaction equation is

2 KMnO4 + 5 H2C2O4 + 3 H2SO4 -------- > 2 MnSO4 + 10CO2 + 8H2O

Using the mole ratio of the H2C2O4 and KMnO4 we can calculate the concentration of the H2C2O4

lets first calculate the moles of the KMnO4 reacted

moles = molarity * volume in liter

moles of KMnO4 = 0.025 mol per * 0.0213 L

                           = 0.000533 mol KMnO4

now using the mole ratio lets calculate the moles of the H2C2O4

mole ratio is 2 mol KMnO4 = 5 mol H2C2O4

0.000533 mol KMnO4 * 5 mol H2C2O4 / 2 mol KMnO4 = 0.001331 mol H2C2O4

now using the moles and volume of the H2C2O4 we can calculate its molarity as follows

moarity = moles / volume in liter

10.0 ml = 0.010 L

so

molarity = 0.001331 mol / 0.010 L

              = 0.1331 M

So the molarity of the H2C2O4 = 0.1331 M