Next, potassium oxalate is added to the washed precipitate. potassium oxalate dissociates into its ions in solution. at high oxalate concentrations, iron(ll) oxalate combines with another oxalate ion to form a soluble complex ion that consists of two oxalate ions joined to the iron(il) ion. hydrogen peroxide is an effective oxidizing agent, accepting two electrons. it will oxidize iron(ii) to iron(lll). this process strips some of the oxalate ion from the iron, so the product is a mixture of fe3+(aq), fec204+(aq), and fe(c204)2- (aq). assume that the predominant product is fe3+(aq). this is a redox reaction; therefore you must balance the electrons (charge) as well as the atoms. the resulting solution is basic, causing some or all of the iron to precipitate as iron(iii) hydroxide, a reddish-brown precipitate. the excess hydroxide ions must be neutralized with oxalic acid. the oxalic acid will also neutralize the hydroxide ions of the iron(iii) hydroxide precipitate, releasing the iron(iii) ion back into solution. oxalic acid is chosen so that no additional anions will be present to interfere with the formation of the complex. the excess oxalate ions convert all iron present into a soluble complex ion with three oxalate ions attached to the iron(lll) ion at this point, there are 3 principal ions remaining in solution, what are they? you will need to trace through all of your steps. answer in a complete sentence. substance and what is its purpose? once the final product ion has been made, one final substance will be added to the solution. what is this the solution will be green at this point due to the formation of the complex fe(c2o4)33 ions. when a positive counter ion, a cation, combines with these, crystals form.