Introduction: For daily living needs, people require to have some Vitamin element from food or drinks. Nowadays, many supermarkets provide some Vitamin products such as Vitamin C tablet, which is necessary for people healthy. Vitamin C pills have become common, because it is a quick way to obtain Vitamin C and it is also a useful way to prevent common cold and pregnancy.
Although Vitamin C tablet has become common, most of people are not know that the exactly amount of per tablet. Through this experiment, the quantity of Vitamin C can be determined. The equation of Vitamin C (C6H8O6) reacts with Iodine: KIO3 + 5KI + 3H2SO4 3I2 + 3K2SO4 + 3H2O. As the formula showed above, Vitamin C will react with the same amount of I2 [3]. In order to all of Vitamin C is reacted, ensure the quantity of I2 is in excess. This experiment is through chemical reaction to analysis the quantity of Vitamin C in each sample tablet.

Procedure

250 mg vitamin C slices in a clean 250 ml beaker and beaker is filled with 100 ml of distilled water. Mixing distilled water until vitamin C tablet was dissolved. When vitamin be dissolved, filter into 250 ml volumetric flask. This beakerand filter paper must wash in distilled water, dilution to mark with distilled water. This bottle is sealed and plug, then mixed solution. Prepare KIO3 dilution. 25 ml concentrated main solutions KIO3, from the previous experiment, is to 250 ml pipette volume antiaircraft gun. This volume is filled with distilled water, until it met mark. A clean burette is filled with Na2S2O3 solutions. 25 ml of dilution KIO3 is pipette into a clean up 250 ml of conical flask, and 0.2 g KI and 1 ml of sulfuric acid was added into the bottle. 10 ml of vitamin C solution is to 250 ml pipette conical flask. The initial reading burette mark down. Na2S2O3 titration into the bottle and agitation flask, until a pale yellow in color. After 3 ml of starch solution added to the bottle, blue color appear. Na2S2O3 always continue to add to the disappearance of the blue. Finally, the final reading is cut burette

Observations and Data

Vitamin C mass per tablet: 250mg
Molar concentration of stock KIO3 solution: 0.0190 M
Molar concentration of dilute KIO3 solution: 0.00190M
Molar concentration of Na2S2O3: 0.009957M Burette Reading

Trial# | 1 | 2 | Final burette reading | 21.6±0.02ml | 21.22±0.02ml | Initial burette reading |