Iodometric titration of copper sulphate with sodium thiosulphate
Answers
Iodometric determination of copper is based on the oxidation of iodides to iodine by copper(II) ions, which get reduced to C u X + . Sodium thiosulphate makes for an inexpensive, safe and effective reducing agent to react with I X 2 . ... This is the reason for the addition of acetic acid and sodium carbonate.
Iodometric titration of CuSO4 with Sodium thiosulfate
Procedure: pipette out aliquot having copper in 250 ml conical Flask.
2. Add Ammonia till solution become deep blue color.
3. Add acetic acid till solution color becomes colorless.
4. Add 2g potassium iodide in it.
5. Put the solution away from the sunlight for 5 minutes.
6. Titrate it against 0.1M Sodium thiosulfate until a pale yellow.
7. Add about 5 ml of starch as an indicator in the Flask.
8. Add about 1gram of Potassium Thiocyanate.
9. Titrate the Solution against titrant until the blue color becomes the colorless solution.