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really urgent help in chemistry exam tomorrow a level

dichromate ions ad managnese ions question at the end of the paper.
http://www.mediafire.com/view/x3yztdjogy1/2815-06_2003_jun_w.pdf
I'm getting the oxidation state of mn after oxidation to be +6 beacuse
3 X 4H+ +mn2+ +so42- ----> mn^n+ + h2o +so2 +2e. To balance charge on both sides oxidation state of Mn must be +6. But in the mark scheme it s +4

Reply 1

nothepreacher

Could someone PLEASE PLEASE answer my question above? I am panicking! Please understand. No one to help me at home

Reply 2

Millie_J

Redox isn't really my forte but if 3 moles of Mn2+ are oxidized by 1 mole of Cr2O7^2- then that means (as the chromium species gains 6 electrons), 3 moles of Mn2+ must lose these 6 electrons. This means that each Mn2+ will lose 2 electrons giving the oxidation state of +4.
Now CALM DOWN panicking makes your brain screw up. Go sleep and good luck!! Xx