Question

Suppose a student needs to standardize a sodium thiosulfate, Na, S,O,, solution for a titration experiment. To do so, he or she will react it with a solution of iodine. The student adds a 1.00 mL aliquot of 0.0200 M KIO, solution to a flask, followed by 3 mL of distilled water, 0.2 g of solid KI, and I mL H, SO. The student then titrates the solution with sodium thiosulfate solution in order to determine the exact concentration of Na,s,o, The end point of the titration is reached after 0.86 mL of Na,s,o, is dispensed from a microburet. What is the concentration of the standard sodium thiosulfate solution? concentration =

Answer 1

32 + 3 H2O 1) I 7 +T tout (Todare in excess 21) I + 25207 - 2E +q q? so ronal reason 2 I ģ + SI tout +6 02- - s I +350 +340. 2) Imoles of I5 = tx moles of so? ) (mku za 2 t* (mxu qoz a) Co-groom x 100ml 62 magzxo.86ml 2) Mar a 0.13953 m. 10-14 m of standard concentration Nasz a 10-14 m.