Experiment 10 - Vitamin C Determination

Procedure:

Part A - Preparation of Standard Thiosulphate, S₂O₃^2-, Solution

1. Zero an empty plastic weighing dish on an analytical balance.
2. Add 2.4 - 2.5 grams of sodium thiosulphate pentahydrate, .
3. Record the mass of the crystal on the data sheet.
4. Transfer the sodium thiosulphate pentahydrate crystal into a clean 100.0 mL beaker as demonstrated in the lab.
5. Dissolve the crystals in about 75 mL of distailled water, stirring gently to dissolve the crystals.
6. Transfer the solution carefully into a 100.0 mL volumetric flask.
7. Make up the volume to the 100.0 mL mark with distilled water, stopper and mix, by inverting the flask 15 times.