783. The content of ascorbic acid in the drug was determined by coulometric titration. To do this, the drug tablet was dissolved in water in a volumetric flask with a capacity of Vk, the volume of the solution was brought to the mark with water and the initial analyzed solution was obtained. An aliquot of this solution with a volume Va was placed in a coulometric cell, an excess of potassium bromide was added, and coulometric titration of ascorbic acid was carried out with electrogenerated bromine at constant current i for time τ.
During the titration, ascorbic acid is oxidized by bromine to dehydroascorbic acid, with one acid molecule reacting with two bromine atoms.
Using the data below, calculate the content (g) of ascorbic acid in a tablet of the drug. The molar mass of ascorbic acid C6H8O6 is 176.13 g/mol.
Variant Vk, ml Va, ml i, mA τ
a 200 10.00 70 6 min 26 s

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