Chapter 5, Problem 95RQ

Hydrogen peroxide, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$, solution can be purchased in drug stores for use as an antiseptic. A sample of such a solution weighing 1.000 g was acidified with ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ and titrated with a 0.02000 M solution of ${\text{KMnO}}_{\text{4}}$. The net ionic equation for the reaction is

${\text{6H}}^{\text{+}}{\text{+5H}}_{\text{2}}{\text{O}}_{\text{2}}+2{\text{MnO}}_4^{-}\to 5{\text{O}}_{\text{2}}{\text{+2Mn}}^{\text{2+}}+8{\text{H}}_{\text{2}}\text{O}$

The titration required 17.60 mL of ${\text{KMnO}}_{\text{4}}$ solution.

(a) How many grams of ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ reacted?

(b) What is the percentage by mass of the ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ in the original antiseptic solution?