Chapter 16, Problem 102E

A 1.012-mL sample of a salt containing ${\text{Fe}}^{2+}$ is titrated with 0.1201 M ${\text{KnO}}_{\text{4}}$. The endpoint of the titration is reached at 22.45 mL. Find the mass percent of ${\text{Fe}}^{2+}$ in the sample. The unbalanced redox reaction that occurs in acidic solution during the titration is:

${\text{Fe}}^{2+}(aq)+{\text{MnO}}_4^{-}(aq)\to {\text{Fe}}^{3+}(aq)+{\text{Mn}}^{2+}(aq)$