How do I write balance equations for this redox reactions Fe2O3 + CO ===> Fe + CO2 in acidic solution?

Question

How do I write balance equations for this redox reactions Fe2O3 + CO ===> Fe + CO2 in acidic solution?

Answer 1

Acidic solution means we can use H+ (acid) to balance the equation.

Here is the half-reaction method.

Fe2O3 + CO ==> Fe + CO2

Fe₂O₃ ==> Fe ... reduction half reaction

Fe₂O₃ ==> 2Fe ... balanced for Fe

Fe₂O₃ ==> 2Fe + 3H₂O ... balanced for O

Fe₂O₃ + 6H⁺ ==> 2Fe + 3H₂O ... balanced for H using H⁺

Fe₂O₃ + 6H⁺ + 6e- ==> 2Fe + 3H₂O ... balanced for charge and is the final balanced half reaction

CO ==> CO₂ ... oxidation half reaction

CO + H₂O ==> CO₂ ... balanced for C and O

CO + H₂O ==> CO₂ + 2H⁺ ... balanced for H using H⁺

CO + H₂O ==> CO₂ + 2H⁺ + 2e- ... balanced for charge and is the final balanced half reaction

Multiply the oxidation half reaction by 3 to equalize the electrons and add the two half reactions...

Fe₂O₃ + 6H⁺ + 6e- ==> 2Fe + 3H₂O

3CO + 3H₂O ==> 3CO₂ + 6H⁺ + 6e-

------------------------------------------------------ add and combine and/or cancel like terms

Fe₂O₃ + 3CO ==> 2Fe + 3CO₂ ... balanced redox equation