[buffy121]

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?

[Borek]

Start with the reaction equation.

[buffy121]

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!

[Borek]

You need to combine them together - it is molar ratio of iodine and ascorbic acid reacting that counts.