An unknown Cu solution was prepared by dissolving 3.1373 g of the sample in a 200.0 mL flask. A 25.00 mL aliquot of this solution was titrated with 0.1084 M Na2S2O4, the titration required 15.93 mL to reach the end point. Calculate the % Cu in the sample?
Start with the 1/2 equations:
Dithionate(III) ions are reducing:
The net oxidation no. change is
These are taken in by the copper(II):
To get the electrons to balance we X
This is the mass of Cu(II) in 25.00 ml.