In order to standardize a KMnO4 solution, 0.3498 g Na2C2O4 was dissolved in 30 mL water and 15 mL 3.0 M H2SO4. The KMnO4 solution was added to the Na2C2O4 solution until a pale pink color persisted. The titration took 29.5 mL of KMnO4 solution. What is the concentration of the KMnO4 solution?

To find the concentration of the KMnO4 solution, we can use the concept of stoichiometry and the balanced equation of the reaction between KMnO4 and Na2C2O4. The balanced equation for the reaction is:

5Na2C2O4 + 2KMnO4 + 8H2SO4 -> 10CO2 + 2MnSO4 + 10Na2SO4 + 8H2O

From the equation, we can see that 2 moles of KMnO4 reacts with 5 moles of Na2C2O4. Therefore, the molar ratio between Na2C2O4 and KMnO4 is 5:2.

Given that you used 0.3498 g of Na2C2O4, we need to convert it to moles. The molar mass of Na2C2O4 is:

(2 x atomic mass of Na) + (2 x atomic mass of C) + (4 x atomic mass of O)
= (2 x 22.99) + (2 x 12.01) + (4 x 16.00) g/mol
= 134.00 g/mol

Using the conversion:

moles of Na2C2O4 = mass of Na2C2O4 / molar mass of Na2C2O4
= 0.3498 g / 134.00 g/mol
= 0.00261 mol

Now, using the mole ratio between Na2C2O4 and KMnO4, we can calculate the number of moles of KMnO4 used in the titration:

moles of KMnO4 = (moles of Na2C2O4) x (2 moles of KMnO4 / 5 moles of Na2C2O4)
= 0.00261 mol x (2 / 5)
= 0.00105 mol

The volume of the KMnO4 solution used in the titration is given as 29.5 mL. To find the concentration, we need to convert this volume to liters:

volume of KMnO4 = 29.5 mL = 29.5 mL / 1000 mL/L = 0.0295 L

Now, we can calculate the concentration of the KMnO4 solution using the equation:

concentration (M) = moles of KMnO4 / volume of KMnO4 (in L)
= 0.00105 mol / 0.0295 L
= 0.0356 M

Therefore, the concentration of the KMnO4 solution is 0.0356 M.