4.7 - Chemistry (OpenStax)

Question

In an acidic solution hydrogen peroxide reacts with Fe⁺² to produce Fe⁺³ and water. Write a balanced equation for this reaction.

Step-by-Step Solution

Answer

Answer

The balanced equation will be

\({H_2}{O_2}\left( {aq} \right) + 2{H^ + }\left( {aq} \right) + 2F{e^{2 + }}\left( {aq} \right) \to 2{H_2}O\left( l \right) + 2F{e^{3 + }}\)

Writing half-reaction

The oxidation half-reaction is: \(F{e^{2 + }}\left( {aq} \right) \to F{e^{3 + }}\left( {aq} \right) + {e^ - }\)

The reduction half-reaction is: \(2{H^ + }\left( {aq} \right) + 2{e^ - } \to 2{H_2}O\left( l \right)\)  

Balancing the equation

The oxidation half-reaction is multiplied by 2 to balance the number of electrons: 

\(2F{e^{2 + }}\left( {aq} \right) \to 2F{e^{3 + }}\left( {aq} \right) + 2{e^ - }\)

Adding both the equation

Adding both the oxidation and reduction half-reactions, the following was obtained:

\({H_2}{O_2}\left( {aq} \right) + 2{H^ + }\left( {aq} \right) + 2F{e^{2 + }} \to 2{H_2}O\left( l \right) + 2F{e^{3 + }}\left( {aq} \right)\)