Outline a procedure for determining what fraction of total iron is dissolved Fe2+, Fe3+, and particulate Fe.?

Answer 1

Your basic experiment is to titrate Fe2+ against KMnO4.
1. Filter off the undissolved iron from a sample, and titrate. This gives you [Fe2+].
2. Again filter off the iron, and add a mild reducing agent. This reduces the Fe3+ to Fe2+, and you now titrate again. The difference between the two is [Fe3+].
3. Take some of the powder, and add excess dilute sulphuric acid (not HCl or HNO3). This will produce Fe2+, and you can titrate again to find how much iron metal there was.