Calculating concentration of diluted solution by titration

[fishfish]

Homework Statement

Hi, I'm a bit confused with which volume to use when calculating the concentration of a diluted solution. In my problem, we're given an unknown concentration of H2O2 to titrate with a given concentration of KMnO4 solution. I have calculated the number of moles of H2SO4 in the solution to be 6.8244 x 10^-4 moles, but I'm confused as to which volume to use to calculate the concentration. The original volume of H2O2 used was 1 mL, but it was diluted with 20mL of water. Do I use 1mL as my volume or do I use 21mL?

Homework Equations

c=n/v

The Attempt at a Solution

 

[Nino MMP]

In this case, you would use 21mL as your volume. This is because the solution was diluted with an additional 20mL of water, so the total volume of the solution that you're working with is now 21mL. Therefore, you would use this volume when calculating the concentration of H2SO4 in the solution.