Chapter 4, Problem 4.118SP

Dichromate ion, $C{r}_2{O}_7^{2-}$ , reacts with aqueous iron(ll) ion in acidic solution according to the balanced equation

$C{r}_2{O}_7^{2-}(aq)+6F{e}^{2+}(aq)+14H^{+}(aq)\to 2C{r}^{3+}(aq)+6F{e}^{3+}(aq)+7H_{2}O(l)$

What is the concentration of $F{e}^{2+}$ if 46.99 mL of 0.2004 M $K_{2}C{r}_2{O}_7$ is needed to titrate 50.00 mL of the $F{e}^{2+}$ solution?