138. Задачка по химии №013 834

101. To determine the content of glucose in the preparation, to the 10.05 mg weighed portion, an excess of iodic acid solution was added to oxidize glucose
C6H12O6 5HIO4 → CH2O 5 HIO3 5HCOH
After the completion of the oxidation reaction, the solution was neutralized with NaHCO3, the excess of HIO4 was bound to Na3AsO3 according to the reaction:
HIO4 Na3AsO3 NaHCO3 → NaIO3 Na3AsO4 CO2 H2o
And, finally, the excess of Na3AsO3 was titrated with 9.64 cm3 of a solution of I2 with C1 / 2 I2) = 0.0510 mol / dm3. To determine the amounts of HIO4 and Na3AsO3 introduced, a blank experiment was carried out with the same volumes of solutions of the above reagents, but without a sample of the preparation. In this case, 2.12 cm3 of the same iodine solution was consumed. Calculate the mass fraction of glucose in the preparation.