Make Iron (II) and (III) Chloride

Here I demonstrate how to make iron (II) chloride, convert it to iron (III) chloride, and then regenerate it back to iron (II) chloride. We'll be needing both of these reagents in an upcoming video.

Very simply, just add some steel wool to hydrochloric acid to produce iron (II) chloride and hydrogen gas:
Fe + 2HCl == FeCl2 + H2
The finer the wool, the faster the reaction will be.

Iron(II) chloride is rather unstable, and will readily oxidize to iron(III) chloride if left out uncovered. This reaction requires hydrochloric acid, but even so I've heard it's extremely hard to keep iron(II) chloride for any length of time.
4FeCl2 + O2 + 4HCl == 4FeCl3 + 2H2O
This reaction can be sped up greatly by introducing oxygen directly into the solution, using 3% drugstore hydrogen peroxide.

Finally, iron(III) can be converted back to iron(II) by adding in some more steel wool. Over a few minutes, this causes the solution to change color from brown back to lime green.