How do we differentiate solutions of #"sodium dichromate"# and #"chromium (III+)"# ion?

1 Answer
Apr 23, 2017

Answer:

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Explanation:

Dichromate ion is #Cr_2O_7^(2-)#. An oxygen bridges 2 metal centres to give a complex ion that I could represent as:

#""^(-)O(""_2O=)Cr-O-Cr(=O)_2O^(-)#.

The oxidation state of each chromium centre is #VI+# (the maximum oxidation number), and this reagent is commonly used an oxidant, and we see the colour of bright orange (the dichromate ion) change to green, #Cr^(3+)#.

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Dichromate salts are typically a beautiful orange colour:

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