A KMnO4 (aq) solution is to be standardized by titration against As2O3 (s). A 0.235 g sample of As2O3 requires 32.15 mL of the KMnO4 (aq) for its titration.
5 As2O3 (aq) + 4 MnO4- (aq) + 9 H2O (l) + 12 H+ (aq) --> 10 H3AsO4 (aq) + 4 Mn2+ (aq)
Prove that this reaction is a redox reaction. Show your work or thought process.
1. Which reactant is the reducing agent?
2. What is the oxidation number of As in the product?
3. Since Group 1 cations are very soluble and often participate as spectator ions in chemical reactions, what is the concentration in (mol/L) of KMnO4?
Useful formulas: Moles = Mass / Molar Mass, Concentration = moles / volume (in L)
HINT: Conversion of moles of As2O3 to KMnO4 will be required to solve this part of the question. KMnO4 and MnO4- will have the same number of moles.