A compound has been isolated that can have either of two possible formulas:

(a) K[Fe(C₂O₄)₂(H₂O)₂] or

(b) K₃[Fe(C₂O₄)₃]. To find which is correct, you dissolve a weighed sample of the compound in acid, forming oxalic acid, H₂C₂O₄. You then titrate this acid with potassium permanganate, KMnO₄ (the source of the MnO₄⁻ ion). The balanced, net ionic equation for the titration is

Titration of 1.356 g of the compound requires 34.50 mL of 0.108 M KMnO₄. Which is the correct formula of the iron-containing compound: (a) or (b)?

Transcribed Image Text:

5 H₂C₂O4(aq) + 2 MnO4 (aq) + 6 H3O+ (aq) → 2 Mn²+ (aq) + 10 CO₂(g) + 14 H₂O(l)