Balance the folowing redox reactions; Mn2+ + MnO2 = MnOOH Fe2+ + MnOOH(s) = Fe3+ + Mn2+

Ans 1.

Below is the given reaction:

{eq}Mn^{2+} + MnO_2 \rightarrow MnOOH \\ i.e. Mn^{2+} + MnO_2 \rightarrow Mn_2H {/eq}

Oxidation half-reaction

{eq}\\ Mn^{2+} \rightarrow MnO_2H {/eq}

• Balancing oxidation half-reaction

{eq}\\ Mn^{2+} + 2H_2O + H^+ \rightarrow MnO_2H + 4H^+ +e^- {/eq}

Reduction half-reaction

{eq}\\ MnO_2 \rightarrow MnO_2H {/eq}

• Balancing reduction half-reaction

{eq}MnO_2 + H^+ +e^- \rightarrow MnO_2H {/eq}

Now, Adding both the equations in such a way that the electrons get canceled out.

{eq}Mn^{2+} + MnO_2 + 2H_2O \rightarrow 2MnO_2H +2H^+ {/eq}

Ans 2.

Below is the given reaction:

{eq}Fe^{2+} + MnO_2H \rightarrow Fe^{3+} + Mn^{2+} {/eq}

Oxidation half-reaction

{eq}Fe^{2+} \rightarrow Fe^{3+} {/eq}

• Balancing oxidation-half reaction

{eq}Fe^{2+} \rightarrow Fe^{3+} + e^- {/eq}

Redox half-reaction

{eq}MnO_2H \rightarrow Mn^{2+} {/eq}

• Balancing redox half-reaction:

{eq}MnO_2H + 4H^+ +e^- \rightarrow Mn^{2+} + 2H_2O + H^+ {/eq}

Now, Adding both the equations in such a way that the electrons get canceled out.

{eq}MnO_2H + 3H^+ + Fe^{2+} \rightarrow Mn^{2+} + 2H_2O+Fe^{3+} {/eq}