How do we quantitatively represent the oxidation of sodium thiosulfate, #S_2O_3^(2-)#, by dichromate ion, #Cr_2O_7^(2-)#?
This is a somewhat complicated redox equation. You should end with
Thiolsulfate is oxidized to sulfate:
Both equations (I think) are balanced with respect to mass and charge (as they must be!).
So I cross multiply to give the overall redox equation (I wish to remove the electrons!) and cancel common reagents:
So at the end of your titration, you should have
Note that in thiosulfate, I have always found it useful to regard the terminal sulfur as the precise analogue of oxygen, which has the