Why is it important that the sequence of addition of reagents be followed? What could possibly go wrong when this is not followed?
Reagents added:
1st: Fe3+ solution
2nd: 2.00 mL 10% NH2OH-HCl (hydroxylamine hydrochloride)
3rd: excess 0.20% 1,10-phenanthroline
4th: 1.00 mL HOAc-NaOAc buffer