A 49.45 mL sample of solution containing Fe2+ ions is titrated with a 0.0103 M KMnO4 solution. It required 23.76 mL of KMnO4 solution to oxidize all the Fe2+ ions to Fe3+ by the following reaction.

Question

MnO4-(aq) + Fe2+(aq) Mn2+(aq) + Fe3+(aq) (unbalanced)
(a) What was the concentration of Fe2+ ions in the sample solution?
(b) What volume of 0.0150 M K2Cr2O7 solution would it take to do the same titration? The reaction is shown below.
Cr2O72-(aq) + Fe2+(aq) Cr3+(aq) + Fe3+(aq) (unbalanced)