Answer
12 mL H2O2
Work Step by Step
After moving the percent to other side of the equation, and multiplying by 400.0mL to isolate, we are left with 12 mL of solute.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.