Question

In test tube 4, there is 4 mL of 0.0350 M KIO3, 5 mL of 0.200 M Ba(NO3)2, the total volume is 12 mL and the absorbance of solution is 2.337. What is the concentration of IO3- in the solution?

Answer 1

This one is fairly simple. We have the initial concentration of KIO₃ and we will use the total volume of the solution to estimate the final concentration.

Intially, the amount of KIO₃ present in mole = (4 mL).(0.0350 mole/ 1 L).(1 L/1000 mL) = 1.4 x 10^-4 mole.

Now, in the final solution, we have the exact same amount of KIO₃ (assuming no other source), but the volume is now 12 mL. So, the concentration of IO₃^- in the final solution is

(1.4 x 10^-4 mole)/(12 mL).(1000 Ml/ 1 L) = 0.0117 M

Ans: The concentration of IO₃^- in the solution is 0.0117 M.