Sodium thiosulfate, , is used as a fixer in photographic film development. The amount of Na2S2O3 in a solution can be determined by titration with iodine, , according to the equation:
The end of the titration is determined by the color. NaI is pale yellow and is deep purple. Just when the yellow color persists, all the iodine that can react has reacted.
What is the concentration of the solution if 37.30 mL of a 0.1970 M solution react exactly with a 100.0 mL sample of the solution? Use 4 significant figures.
