Help? Using the half-reactions given in equations 1 & 2, write the balanced net ionic equation for the reaction of sodium oxalate and potassium permanganate.

Question

1) 8H⁺ + MnO₄^- + 5e^- → Mn²⁺ + 4H₂O

2) H₂C₂O₄ → 2CO₂ + 2H⁺ + 2e^-

Answer 1

To get the net ionic equation the electrons for equations 1 and 2 must be the same.

To get the electrons to be the same you use the least common factor. So since the number of electrons in equation 1 is two and for equation 2 there are 5 electrons , the least common factor would be 10,

So multiple equation 1 by 2 and multiply equation 2 by 5.

Equation 1: 2 x (8H⁺ + MnO₄^- + 5e^- → Mn²⁺ + 4H₂O)

16H⁺ + 2MnO₄^- + 10e^- → 2Mn²⁺ + 8H₂O

Equation 2: 5 x ( H₂C₂O₄ → 2CO₂ + 2H⁺ + 2e^-)

(5H₂C₂O₄ → 10CO₂ + 10H⁺ + 10e^-

Lastly, once the electrons are equal, add both equations and cancel out like terms to get the net ionic equation

16H⁺ + 2MnO₄^- + 10e^- → 2Mn²⁺ + 8H₂O

5H₂C₂O₄ →10CO₂ + 10H⁺ + 10e^-

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Net ionic equation: 6H⁺ + 2MnO₄^- + 5H₂C₂O₄ → 2Mn²⁺ + 8H₂O + 10CO₂