I have this lab due tomorrow and I'm a bit confused on calculating the concentrations.

Background:

It was a 2 stage reaction equations are as followed:

(1) Io

_{3}^{-}_{(aq)} + 3HSO

_{3}^{-}_{(aq)} I

^{-}_{(aq)} + 3SO

_{4}^{2-}_{(aq)} + 3H

^{+}_{(aq)}(2) 5I

^{-}_{(aq)} + 6H

^{+}_{(aq)} IO

_{3}^{-}_{(aq)} 3I

_{2}_{(aq)} + 3H

_{2}O

We had had 2 Solutions named A and B, we're given that Solution A has IO

_{3}^{-} ion and Solution B has 3HSO

_{3}^{-} ion and soluble starch.

We would then mix A and B (10 mL each) thoroughly and time how long it would take to react, we repeated this multiple times diluting Solution A with distilled water with ratios of 9:1, 8:2, and so on to 5:5. My teacher wants me to find the concentration of IO

_{3}^{-} ions in the 20 mL mixture we created, and I have zero clue where to start. Thanks for any help.