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Topic: Ascorbic Acid  (Read 3676 times)

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Offline buffy121

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Ascorbic Acid
« on: August 14, 2009, 06:27:23 AM »
I have to determine the ascorbic acid content of vitamin C using a titration:

The vitamin C tablet weighed 0.745g. We then crushed it and added 200ml of distilled water. Then put 50ml in a beaker and titrated it with 0.081 molar iodine.

The average amount of iodine needed to turn the solution blue was 6.55ml.

Does anyone know how to calculate the moles of ascorbic acid in the tablet, and then the mass of ascorbic acid in the tablet?


Offline Borek

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Re: Ascorbic Acid
« Reply #1 on: August 14, 2009, 07:06:21 AM »
Start with the reaction equation.
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Offline buffy121

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Re: Ascorbic Acid
« Reply #2 on: August 14, 2009, 07:13:17 PM »
Well i think the two redox equations are:

C6H8O6  ---->  C6H6O6 + 2H+ + 2e-

and:

I2 + 2e-  ---->  2I-

But i'm not sure what to do next, if anyone does please tell me!
« Last Edit: August 14, 2009, 07:33:00 PM by buffy121 »

Offline Borek

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Re: Ascorbic Acid
« Reply #3 on: August 15, 2009, 02:56:11 AM »
You need to combine them together - it is molar ratio of iodine and ascorbic acid reacting that counts.
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