(I) Standardization of Na₂S₂O₃ (Hypo)

1. Take a clean and dry conical flask.
2. Pipette out 10 ml CuSO₄ into a clean, dry conical flask.
3. Add 5 ml of KI solution; a dark yellowish-brown color appears.
4. Titrate this solution against hypo until it becomes light yellow.
5. Add 1–2 drops of starch indicator (blue color appears).
6. Continue titration until the color changes to milky white (endpoint).
7. Repeat the titration to obtain concordant readings.

(II) Titration of Unknown CuSO₄ Solution

Repeat the above steps using the unknown CuSO₄ sample in place of the known solution.

Slide-1 Procedure

1. In the conical flask already containing Copper sulphate (CuSO₄) solution.
2. The colour of solution turns brown colour.

Slide-2 Procedure

1. Set the normality of copper sulphate (CuSO4) solution, To start titration click on the start button.
2. Fix the nozzle opening size by nozzle open slider.Shake the flask while Titrating.
3. Titrate the solution till it turn to light yellowish colour.
4. NOTE: Notice this how much volume transfer from burette.
5. for titration Click on start button.

Slide-3 Procedure

1. Add few drops of Starch solution in the conical flask.
2. The colour of solution turns navy blue

Slide-4 Procedure

1. Continue the titration.
2. Titrate it till the colour changes to colorless

Safety Precautions

1. Use distilled water throughout the experiment.
2. Use the same volume of starch indicator in each titration.
3. Prepare the starch indicator freshly.
4. Observe the endpoint carefully.

Clean-Up

1. Dispose of waste solutions properly.
2. Clean and return all glassware to its designated place.