Complete and balance the following half-reaction in basic solution

Question

Mn²⁺(aq) to MnO_2(s)

_{I got Mn^2+ + 2H2O to MnO2 + 4H+ +2e- but it says I'm wrong and I only have 1 try left}

Answer 1

Mn²⁺(aq) ===> MnO_2(s)

First balance the oxygens:

Mn²⁺ + 2H₂O ==> MnO₂

Then balance hydrogen:

Mn²⁺ + 2H₂O ==> MnO₂ + 4H⁺

Since this is taking place in base, for each H+ we must add OH-

Mn²⁺ + 2H₂O + 4OH^- ==> MnO₂ + 4H⁺ + 4OH^-

Finally, balance the charge:

Mn²⁺ + 2H₂O + 4OH^- ==> MnO₂ + 4H⁺ + 4OH^- + 2e-

This equation reduces to the following:

Mn²⁺ + 4OH^- ==> MnO₂ + 2H₂O + 2e-

This should be the correct response. Since you have only one shot left, I sure hope it’s right. Also, I hope you see your mistake.