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Question

The quantity of antimony in an ore can be determined by an oxidation‑reduction titration with an oxidizing agent. The ore is dissolved in hot, concentrated acid and passed over a reducing agent so that all of the antimony is in the form of Sb3+(aq) . The Sb3+(aq) is completely oxidized by an aqueous solution of BrO−3(aq) . 

Complete and balance the equation for this reaction in acidic solution.

According to program this is incorrect: BrO₃^- + 3H2O + 3Sb³⁺ ==> Br^- + 6OH^- + 3Sb⁵⁺

^{(This is an answer from another post on this website)}

Answer 1

Sb³⁺ + BrO₃^- ==> Sb⁵⁺ + Br^- ... unbalanced equation

Using the half reaction method:

Sb³⁺ ==> Sb⁵⁺ + 2e- ... oxidation half reaction

BrO₃^- + 6H⁺ + 6e- ==> Br^- + 3H₂O ... reduction half reaction

Multiply oxidation rxn by 3 to equalize electrons and add the two equation together:

3Sb³⁺ ==> 3Sb⁵⁺ + 6e-

BrO₃^- + 6H⁺ + 6e- ==> Br^- + 3H₂O

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3Sb³⁺ + BrO₃^- + 6H⁺ ==> 3Sb⁵⁺ + Br^- + 3H₂O ... balanced redox equation