Wow.. as long as you don't add too much aq. KMnO4 into your test solution, you will observe a colour change from green to yellow as Fe2+ oxides to Fe3+. If you add excess aq. KMnO4, your entire test solution will just turn purple. I will provide you with 2 redox equations. You do the balancing yourself to arrive at the final chemical equation:
Assuming acidic conditions,
1) Fe2+ -> Fe3+ + e-
2) MnO4- + 8H+ + 5e- -> Mn2+ + 4H2O
(If you use alkali aq. KMnO4 instead of acidified aq. KMnO4, you would observe a brown precipitate, ie. Fe(OH)3, formed)