Vitamin C

Topics: Vitamin C, Titration, Ascorbic acid Pages: 5 (971 words) Published: August 11, 2011
Does the amount of Vitamin C on the label of commercially available tablet exaggerate the amount of Vitamin C?

The aim of this experiment is to determine whether manufacturers of commercially available Vitamin c tablets exaggerate the amount of vitamin C

The purpose of this experiment was to test Vitamin C in commercially available Vitamin C tablets. It was discovered that the percentage Vitamin C content was lower than what was stated on the label. This, however, could be due to fillers and ionization, amongst other variables.


Hypothesis: The amount of Vitamin C in the tablet is not exaggerated

Independent variable:

Dependent variable:

Fixed variables:

Indicator used: Phenolphthalein

ï‚· Burette
ï‚· Pipette
ï‚· Beaker
ï‚· Ehlernmeyer flasks
ï‚· Glass rod (stirring rod)
ï‚· Vitamin C tablet
ï‚· Standard solution: 0,1mol.dm3 NaOH
ï‚· Warm water
ï‚· Indicator: phenolphthalein

1. Crush one Vitamin C tablet, put it on a page and weigh it (take the mass of the page into consideration. Record the mass 2. Pour 75ml warm water into beaker
3. Mix the crushed tablet with the water using a glass rod
4. Fill the burette with standard solution (NaOH) up to the zero mark (make sure the tap is closed) 5. Run some NaOH solution out of the burette to allow the solution to flow through the tap as well. Record the amount of solution you have left in the burette 6. Attach the burette to a stand

7. Pipette 25ml Vitamin C solution into an Ehrlenmeyer flask 8. Add 4-5 drops of phenolphthalein
9. Put the flask underneath the burette with ample space for stirring 10. Open tap to pour standard solution into the flask.
11. Stir continuously
12. When the colour change starts to become more obvious and permanent, slow down, adding one drop at a time eventually 13. Record the amount of NaOH solution in the burette
14. Repeat steps 7-13 a minimum of 2 more times


Vitamin C content on label: 600mg
Mass of crushed Vitamin C tablet: 1100mg
Water and Vitamin C solution: 75ml (25ml per trial)
Drops of phenolphthalein: 5
NaOH concentration: 0,1mol.dm3

Table showing the readings of NaOH (base) solution in the burette

Initial Reading (mol.dm3)015,531
Final Reading (mol.dm3)15,53146,5
Volume of base used (mol.dm3)15,515,515,5

Average volume of base used: 15,5mol.dm3

Balanced equation: H2C6H6O6 + NaOH  NaHC6H6O6 + H2O

c= n/v
0,1= n/15,5
n= 1,55 mols NaOH


Volume of acid= 25ml

c= n/vM= 2(1)+6(12)+6(1)+6(16)
= 1,55/25 = 176 amu Ascorbic acid
= 0,062mol.dm3

n= m/M gX1000= mg
1,55= m/176272,2g X 1000= 272200mg
m= 272,2g

The label says the Vitamin C content is 600g

Therefore the actual % Vitamin C content= 272,2/600 X 100
= 45,3% Vitamin C

In accordance with my results, the Vitamin C content in these tablets is exaggerated. However, there are factors that could alter these results, making them inaccurate. I therefore conclude that no conclusion has been made, until further experiments prove otherwise.

Vitamin C tablets are used to supply the body with the necessary amount Vitamin C that it didn’t get through diet. Vitamin C repairs and replenishes many organs, it is necessary for functions such as the biosynthesis of collagen and many more, and it prevents many diseases (such as scurvy). Too much Vitamin C can also be unhealthy and lead to problems, although most of the waste nutrients are excreted.

It is, by law, that the Vitamin C content is stated on the packaging but whether or not the amount is correct, is unknown. Titration help us to calculate the actual amount of Vitamin C in a tablet but this could be inaccurate. Vitamin C ionizes easily, even more so in warm water. Therefore the amount of Vitamin C in the tablet could be higher because of this...
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