When standardizing an iodine solution, 30.37 mL of the solution was required to

completely oxidize 10.00 mL of a 5 mg/mL solution of ascorbic acid. What is the

molarity of the titrant?

First thing, we need to know the chemical equation for the titration reaction and it is as follows:

KIO3 (aq) + 6 H + (aq) + 5 I - (aq) = 3 I2 (aq) + 3 H2O (l) + K + (aq)

C6H8O6 (aq) + I2 (aq) = C6H6O6 (aq) + 2 I - (aq) + 2 H + (aq)

We are given the amounts and the concentrations. We use these values to calculate what is needed. We calculate as follows:

5 mg/mL C6H8O6 (10.0 mL) (1 g / 1000 mg) (1 mol / 176.14 g) (1 mol I2 / 1 mol C6H8O6) (1 mol KIO3 / 3 mol I2) = 9.46x10^-5 mol KIO3 needed

Molarity = 9.46x10^-5 mol KIO3 /.03037 L = 0.003 M KIO3