Question number 78:

A) 1.022 g of KIO3 was diluted to 500 mL with water. Then 50 mL of this solution was pipetted and treated with excess of KI (2g) and 10 mL of 0.5 M sulfuric acid. Then the liberated I3- was tirated with 37.66 mL of Na2S2O3 in presence of starch indicator. So knowing all this, what is the concentration of Na2S2O3 solution?

B) 1.233 g sample of solid containing ascorbic acid and inert ingredients was dissolved in dilute sulfuric acid and treated with 2 g of KI and 50 mL of potassium iodate prepared in A). Excess of liberated I3- was tirated with 14.22 mL of Na2S2O3 prepared also in part A). Find the weight percentage of ascorbic acid (176 g/mol) in the sample?