Question

Redox titration of oxalate

1.00g of K3[Fe(C2O4)3] (Molar mass 437.25g/mol)

Mixed with 20ml .984M sulfuric acid.

TItrated with 13.4ml .028MKmNO4

-----

What is

Moles of KMnO4 reduced?

Moles of C2O42 oxidized?

Mass of C2O42 oxidized?

Actual weight % C2O42 in KTOF3

Theoritical weight % of C2O42 in KTOF3

%Error of weight % of C2O42 in KTOF3

Answer 1

1.00g of K3[Fe(C2O4)3] (Molar mass 437.25g/mol) corresponds to of K3[Fe(C2O4)3] that contains

Moles of KMnO4 reduced

Thus, 2 moles of KMnO4 oxidises 5 moles of oxalate ions.

0.00038 moles of KMnO4 will oxidise of oxalate ions.

Here, KMnO4 is the limiting reagent and K3[Fe(C2O4)3] is the excess reagent.

Molar mass of

Mass of

Hence, 0.083 g of oxalate ions are oxidised.

Actual weight percent of oxalate ions in KTOF3 %

Theoretical weight percent of oxalate ions in KTOF3 %

Percent error of weight percent of oxalate ions in KTOF3 %

Note: The huge percent error is because much lower (than required) quantity of KMnO4 is used. The reaction mixture still has unoxidized oxalate ions. If we use more amount of KMnO4, they will also be oxidized. This will reduce percent erro.