Balance the redox reaction in basic solution: CN^- + MnO_4^- rightarrow CNO^- +

Question

Balance the redox reaction in basic solution: CN^- + MnO_4^- rightarrow CNO^- + MnO_2 1. Separate the equation into two half-reactions 2. Balance the atoms other than O and H in each half-reaction 3. Add H_2 O to balance O atoms and H' to balance H atoms 4. Add electrons to one side of each half-reaction to balance the charges 5. If necessary, equalize the number of electrons in the two half-reactions by multiplying the half-reactions by appropriate coefficients 6. Add the two half-reactions together and balance the final equation by inspection. 7. For reactions in basic solutions, odd OH^- to both sides of the equation for every H^* that appears in the final equation.

Explanation / Answer

Balancing the chemical equation,

CN- + MnO4- --> CNO- + MnO2

first half reaction,

CN- --> CNO-

balance O,

CN- + H2O --> CNO-

balance H,

CN- + H2O --> CNO- + 2H+

In basic medium, add OH-,

CN- + 2OH- --> CNO- + H2O

Add electrons,

CN- + 2OH- --> CNO- + H2O + 2e-

second half reaction,

MnO4- --> MnO2

balance O,

MnO4- --> MnO2 + 2H2O

balance H,

MnO4- + 4H+ --> MnO2 + 2H2O

In basic medium add OH-,

MnO4- + 2H2O --> MnO2 + 4OH-

Add electrons,

MnO4- + 2H2O + 3e- --> MnO2 + 4OH-

Multiply first half reaction with 3 and second with 2 and add them together,

3CN- + 6OH- --> 3CNO- + 3H2O + 6e-

2MnO4- + 4H2O + 6e- --> 2MnO2 + 8OH-

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3CN- + 2MnO4- + H2O --> 3CNO- + 2MnO2 + 2OH-

Is the net balanced equation

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