Amateur Chemist
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Basic question about Dichromates
In the water treatment plants they use Ferrous Sulfate to treat Sodium Dichromate to change the Chrome VI to Chrome III to make it safer.
My question is what would you call this mixture of Ferrous Sulfate and Sodium Dichromate? and will it be its chemical numenclature.
Thanks
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woelen
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A mixture of ferrous sulfate and sodium dichromate is not stable. That, however, is the purpose of adding the ferrous sulfate. The ferrous ions are
oxidized by the dichromate ion, which themselves are reduced to chromium(III) ions. If enough ferrous sulfate is added, then all dichromate is
converted to the much less toxic chromium(III).
I do not know of a specific name of a solution to which sodium dichromate and ferrous sulfate are added.
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ScienceSquirrel
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You can titrate ferrous salts with dichromate, chromium III and iron III is formed.
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blogfast25
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What indicator would you use? I can do potentiometric titrations but they're a hassle to set up (with my primitive set up).
Easier I think is oxidation of excess iodide to iodine with known volume of dichromate, followed by titration of iodine with thiosulphate and starch.
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ScienceSquirrel
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An example procedure of an iron II versus dichromate titration;
http://wwwchem.uwimona.edu.jm/lab_manuals/c10expt31.html
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blogfast25
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Thanks!
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