a) A solution of sodium thiosulfate, Na2S2O3, is 0.1047 M. 18.59 mL of this solution reacts with 38.62 mL of I2 solution. What is the molarity of the I2 solution?
2(Na2S2O3) + I2↔Na2S4O6 + 2(NaI)
b) 26.64 mL of the I2 solution from above is required to titrate a sample containing As2O3. Calculate the mass of As2O3 (197.8 g/mol) in the sample.
As2O3 + 5(H2O) + 2I2 → 2(H3AsO4) + 4HI