(a) Potassium iodate solution was prepared by dissolving 1.022 gof KIO3 (FM 214.00) in a 500 mL volumetric flask. Then 50.00 mL ofthe solution was pipetted into a flask and treated with excess KI(2 g) and acid (10 mL of 0.5 M H2SO4). How many millimoles of I3−are created by the reaction
b) The triiodide from part (a) reacted with 37.57 mL of Na2S2O3solution. What is the concentration of the Na2S2O3 solution?
(c) A 1.223 g sample of solid containing ascorbic acid and inertingredients was dissolved in dilute H2SO4 and treated with 2 g ofKI and 50.00 mL of KIO3 solution from part (a). Excess triiodiderequired 14.30 mL of Na2S2O3 solution from part (b). Find theweight percent of ascorbic acid (FM 176.13) in the unknown.
HINT: Think \"back-titration
