Calculate the weight percent of ascorbic acid in a tablet of Vitamin C from the following data:
A 136.6 mg sample of a crushed Vitamin C tablet was dissolved in 40 mL of H2SO4 and 20 mL of water. Two grams of KI and 25.00 mL of 0.0155 M KIO3 solution was added, and the mixture titrated to a starch endpoint. The titration required 20.34 mL of 0.0491 M thiosulfate solution.