Ascorbic acid (vitamin C, MM= 176.126 g/mole) is a reducing agent, reacting as follows:
C6H8O6 —-> C6H6O6 + 2H+ + 2e-
The concentration of ascorbic acid can be determined by oxidation with a standard solution of I2 (2 I- —> I2 +2e-). A 200.0 mL sample of citrus fruit drink is acidified and 10.00 mL of 0.0500 M I2 is added. after the reaction is complete, the excess I2 is titrated with 38.62 mL of 0.0120 M Na2S2O3 according to the following reaction:
I2 + 2 S2O3^2- —> 2I- +S4O6^2-
Calculate the number of milligrams of ascorbic acid per milliliter of fruit drink. Assuming the RDA for an adult is 60 mg of ascorbic acid, how much of the fruit drink would be needed to attain the RDA?
