The oxidation of iron(II) hydroxide (Fe(OH)2) to iron(III) hydroxide (Fe(OH)3) can be represented by the following balanced chemical equation:
4 Fe(OH)2 + O2 + 4 H2O → 4 Fe(OH)3
In this reaction, iron(II) hydroxide reacts with oxygen (O2) in the presence of water (H2O) to form iron(III) hydroxide. Initially, Fe(OH)2 appears as a greenish precipitate. Over time, it is exposed to oxygen in the air, which leads to its oxidation to the yellowish-brown iron(III) hydroxide. This process emphasizes the importance of oxygen in the environment and how it can affect chemical compounds over time.