-The concentration of an aqueous solution of NaOCl can be determined by a redox titration with iodide ion in acidic solution: OCl^- (aq)+ 2 I^- (aq)+ 2 H⁺ (aq)→ Cl⁻ (aq)+ I₂ (aq)+ H₂O (l) Assume that the black spheres in the buret represent I⁻ ions,the gray spheres in the flask represent OCl⁻ ions,the concentration of the I⁻ ions in the buret is 0.120 M,and the volumes in the buret and the flask are identical.What is the concentration of the NaOCl in the flask,and what fraction of the I⁻ solution in the buret must be added to the flask to react with all the OCl⁻ ions? A)0.0400 M NaOCl;1/3 of the I⁻ must be added. B)0.0400 M NaOCl;2/3 of the I⁻ must be added. C)0.0600 M NaOCl;1/3 of the I⁻ must be added. D)0.0600 M NaOCl;2/3 of the I⁻ must be added.

Question

Quizplus · Accepted Answer

The balanced chemical equation shows that 2 moles of I⁻ are required to react with 1 mole of OCl⁻. Therefore, the concentration of NaOCl will be half that of I⁻ if the volumes are identical. Given the concentration of I⁻ is 0.120 M, the concentration of NaOCl is 0.060 M. Since 2 moles of I⁻ are needed for each mole of OCl⁻, 2/3 of the I⁻ solution must be added to react with all the OCl⁻ ions.

-The Concentration of an Aqueous Solution of NaOCl Can Be