Complete and balance the following redox reaction in acidic solution. Be sure to include the proper phases for all species within the reaction.

Question

ReO4^-(aq)+MnO2(s)==>Re(s)+MnO4^-(aq)

Answer 1

I'll leave phases to you, just as I did in my previous answer to your other question.

ReO₄^- ==> Re(s) ... reduction half reaction

MnO₂ ==> MnO₄^- ... oxidation half reaction

ReO₄^- ==> Re(s) + 4H₂O ... balanced for Re and O

ReO₄^- + 8H⁺ ==> Re(s) + 4H₂O ... balanced for Re, O and H using acid (H⁺)

ReO₄^- + 8H⁺ + 7e- ==> Re(s) + 4H₂O ... balanced reduction reaction

MnO₂ + 2H₂O ==> MnO₄^- ... balanced for Mn and O

MnO₂ + 2H₂O ==> MnO₄^- + 4H⁺ ... balance for Mn, O and H using acid (H⁺)

MnO₂ + 2H₂O ==> MnO₄^- + 4H⁺ + 3e- ... balanced oxidation reaction

Multiply reduction reaction by 3 and oxidation reaction by 7 to equalize electrons:

3ReO₄^- + 24H⁺ + 21e- ==> 3Re(s) + 12H₂O

7MnO₂ + 14H₂O ==> 7MnO₄^- + 28H⁺ + 21e-

Add and/or cancel like terms to get:

3ReO₄^- + 7MnO₂ + 2H₂O ==> 3Re(s) + 7MnO₄^- + 4H⁺ ... BALANCED REDOX EQUATION