Question

In Experiment 26 saturated solutions of barium iodate at equilibrium were prepared. A student carefully withdrew 5 mL from one of these solutions. That 5 mLs of solution was then treated with a reducing agent and its absorbance at 500nm was measured as 0.51. A Beer’s Law calibration curve showing the relationship between the concentration of IO3- and the absorbance of the treated solution, yielded a k = 380 M^-1 with an intercept through the origin (0,0).

What is the concentration of [IO3-] in the sample?

IO3- itself is clear in solution with no measurable absorbance at 500nm. What is the reaction that produces an absorbing species, and what is the species (i.e. molecule) whose absorbance is measured at 500nm?

After mixing Ba2+ and IO3- to create the initial solution saturated with Ba(IO3)2, the student waited at least 15 minutes before carefully taking a sample of the solution. Specifically how would the concentration of [IO3-] (as determined from the absorbance of the solution) and the calculated Ksp value be affected if the student inadvertently transferred undissolved Ba(IO3)2?