What is the molarity of a potassium triiodide solution,KI₃(aq) ,if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution,K₂S₂O₃(aq) ? The chemical equation for the reaction is:
2 S₂O₃^2-(aq) + I₃^-(aq) → S₄O₆^2-(aq) + 3 I^-(aq) .

Question

Quizplus · Accepted Answer

The balanced chemical equation is:2 S₂O₃^2-(aq)+ I₃^-(aq)→ S₄O₆^2-(aq)+ 3 I^-(aq).From the stoichiometry of the balanced chemical equation, we can see that 2 moles of S₂O₃^2- react with 1 mole of I₃^-. Therefore, the number of moles of I₃^- in 30.00 mL of the KI₃ solution is:n(I₃^-) = (25.00 mL)(0.200 M)(2 mol S₂O₃^2-/1 mol I₃^-) = 1.00 x 10^-3 molThe molarity of the KI₃ solution is:M(KI₃) = n(I₃^-)/V(KI₃) = (1.00 x 10^-3 mol)/(30.00 mL) = 0.0833 MTherefore, the correct choice is A.

What Is the Molarity of a Potassium Triiodide Solution,KI3(aq),if 30

What Is the Molarity of a Potassium Triiodide Solution,KI₃(aq),if 30