a few weeks ago i analyzed hydrogen peroxide in detergents with potassium permanganate. i used sodium oxalate to calibrate my solution.
in one of my oxalate titrations i added permanganate too quickly and my solution turned orange-brown with black precipitates(before calculated end point). where could this color come from?
titrated 0.1994 grams of disodium oxalate : 1.49E-3 mole
orange color appeared after titrating 23.4 ml in less than 10s of permanganate 0.0181M for a total of 4.23E-4 mole. theoreticaly needed 5.95E-4 mole