When this reaction happens colour changes Yellow+Brown to Blood Red?? And What happens when adding Fe powder to the it?? Colour changes or Nothing happen????
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When a source of iron(III) ions is combined with thiocyanate ions, SCN^-, a complex ion is formed, FeSCN^2+, which is dark red.
Fe2+ + SCN- --> FeSCN^2+
With the addition of iron metal to the solution, you are suggesting that there may be a reaction between iron(III) and iron metal to make iron(II). The reduction potentials would seem to support that.
Fe3+ + 1e- --> Fe2+ ......... E = +0.77V
Fe(s) --> Fe2+ + 2e- ......... E = +0.41V
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Fe(s) + Fe3+ --> 2Fe2+ .... E = +1.18V
With the addition of iron metal, the FeSCN^2+ is reduced and the blood-red color disappears.
Fe2+ + SCN- --> FeSCN^2+
With the addition of iron metal to the solution, you are suggesting that there may be a reaction between iron(III) and iron metal to make iron(II). The reduction potentials would seem to support that.
Fe3+ + 1e- --> Fe2+ ......... E = +0.77V
Fe(s) --> Fe2+ + 2e- ......... E = +0.41V
------------------ ------------------ ------------------------
Fe(s) + Fe3+ --> 2Fe2+ .... E = +1.18V
With the addition of iron metal, the FeSCN^2+ is reduced and the blood-red color disappears.