Suppose 25.00 mL of an aqueous solution of iodine was titrated with 0.0250 m Na₂S₂O₃(aq), with starch as the indicator. The blue color of the starch–iodine complex disappeared when 18.33 mL of the thiosulfate solution had been added. What was the molar concentration of I₂ in the original solution? The titration reaction is I₂(aq) +2 S₂O₃ ^2–(aq) →2 I₂(aq) + S₄O₆ ^2–(aq).