Sciencemadness Discussion Board

Balancing A Redox...

ScienceHideout - 28-10-2011 at 17:46

Can someone go thru step-by-step?

MnO4[-] + CH3OH ---> Mn[2+] + HCO2H

My girlfriend wants me to explain this and I suck at explaining redox balancing and those half eqtns and acid mediums... Maybe she would get it if you guys could explain...

hkparker - 28-10-2011 at 18:29

Are we in acidic conditions?

ScienceHideout - 28-10-2011 at 18:48

Yes we are!

hkparker - 28-10-2011 at 23:21

Ok, lets do it. I think you should work through it step by step though as well, so lets do the first step.

Separate the reaction into an oxidation reaction and a reduction reaction.

Oxidation is the loss of electrons (and therefore the increase in charge) and reduction would be the opposite. Look for the element's oxidation states in everything and find where the changes are, separating into two reactions.

woelen - 30-10-2011 at 03:09

Write down the half reaction from permanganate to manganese(II). Acid is consumed in this reaction. Do the same for the half reaction for methanol to formic acid. Then multiply both half reactions such that consumption and production of electrons is the same for both reactions. Using these multipliers, add the two reactions.

Magpie - 30-10-2011 at 08:03

Remember that in aqueous acidic conditions H+ and H2O can be added as necessary to balance the half-reactions. Charge will also balance in these half reactions, and in the combined reaction.

Then there is the matter of carbon's valence. Remember that adding bonds to hydrogen reduces carbon.

[Edited on 30-10-2011 by Magpie]