Question

MnO4- + H2O2 → Mn2+ + O2 The above reaction was used for a redox titration. At the equivalence point 5.684 x 10-4 mol KMnO4 was required to titrate 5.00 mL of H2O2 solution. Calculate the [H2O2].

Answer 1

ANSWER -

In the balanced chemical equation for the reaction between MnO4- and H2O2:

MnO4- + H2O2 → Mn2+ + O2

We can see that the stoichiometry between MnO4- and H2O2 is 1:1. Therefore, the number of moles of H2O2 present in the solution is equal to the number of moles of KMnO4 added at the equivalence point.

Given that 5.684 x 10^-4 mol of KMnO4 was required to titrate 5.00 mL of H2O2 solution, we can calculate the number of moles of H2O2 in the solution:

5.684 x 10^-4 mol KMnO4 = 5.00 mL H2O2 × [H2O2] × (1 L/1000 mL)
[H2O2] = 5.684 x 10^-4 mol / 5.00 × 10^-3 L = 0.11368 M

Therefore, the concentration of H2O2 in the solution is 0.11368 M.

Answer 2

At the equivalence point, 5.684 x 10^-4 mol of H2O2 is present in 5.00 mL of solution. Thus, the concentration of H2O2 is 0.1137 mol/L or 1.14 x 10^-1 M.

Step-by-step explanation:

The balanced chemical equation for the reaction is:

MnO4^- + H2O2 → Mn2+ + O2

From the equation, we can see that the stoichiometry of the reaction is 1:1, meaning that 1 mole of KMnO4 reacts with 1 mole of H2O2. Therefore, the number of moles of H2O2 present in the 5.00 mL solution can be calculated as:

moles of H2O2 = moles of KMnO4 = 5.684 x 10^-4 mol

To find the concentration of H2O2, we can use the following equation:

moles of solute = concentration × volume

Rearranging the equation to solve for the concentration:

concentration = moles of solute / volume

Substituting the given values:

concentration of H2O2 = moles of H2O2 / volume of H2O2 = 5.684 x 10^-4 mol / 5.00 mL

Converting mL to L:

volume of H2O2 = 5.00 mL = 5.00 x 10^-3 L

Substituting the values:

concentration of H2O2 = (5.684 x 10^-4 mol) / (5.00 x 10^-3 L) = 0.1137 mol/L

Therefore, the concentration of H2O2 is 0.1137 mol/L, or 1.14 x 10^-1 M (to 3 significant figures).