[Stivan]

Hello everybody. I have been having some problems with this question; since I was doing a titration lab, I believe it has to do with it. For the question, I have to write how samples containing elemental iron and iron +3 in the oxidation state might be analyzed for their iron content.

[Alpha-Omega]

You have not indicated the matrix of your sample.  Is it solid...and requires digestion?  Is it liquid?  You indicate it contains elemental iron....please elaborate.

However, here is a method for the redox titration of ferrous ammonium sulfate...usually iron sample have Fe(II) and Fe(III)...the KMnO4 will oxidize all the Fe(II) to Fe(III).  KMnO4 is a strong oxidizer and is itself reduced in the reaction.

In this case:  You must titrate the Fe2+/Fe3+ mixture with KMnO4 in acidic solution.The mixture will use the permangamante during the oxidation of Fe(II) to Fe(III). When all Fe(II) has dissapeared the solution will turn violet (KMnO4 in excess), then stop the titration. The amount of permanganate used is to find the amount of Fe(II). Anything in excess of that was Fe(III) from the beginning.

Place to start:  http://www.sas.upenn.edu/~tloschia/AP/labs/iron-redox.htm

[Stivan]

Wow... Thanks a lot. And I am sorry for not mentioning it was in a liquid state. But still you figured it out and knew it was KMnO4. Again thank you.

[Alpha-Omega]

For future reference:  It really helps if you put the subscripts in that indicate the state of the reactants and products....there are some very tricky redox reactions wher the metals are actually in the MOLTEN state...and thay have to be treated as liquids because they are IONIC...and the electrons will participate in the REDOX Reaction....

[AWK]

Hello everybody. I have been having some problems with this question; since I was doing a titration lab, I believe it has to do with it. For the question, I have to write how samples containing elemental iron and iron +3 in the oxidation state might be analyzed for their iron content.

Water solution cannot contain an elemetal iron, eventualy iron(II) and iron(III) only.
This analysis can be done using combination of manganometric and iodometric titrations

[Alpha-Omega]

Iodometric Titration DEFINED:

http://www.csudh.edu/oliver/che230/labmanual/copbrass.htm

Manganometric Titration DEFINED: 

http://www.ipn.uni-kiel.de/abt_chemie/icho/IChO_2004/prepprobs/IChO_Ger_PrepProbs_35-37.pdf