4 FeSO₄ (aq) + 8 NaOH (aq) + O₂ (g) → 2 Fe₂O₃ (s) + 4 Na₂SO₄ (aq) + 4 H₂O (l)

This is an oxidation-reduction (redox) reaction:

FeSO₄ is a reducing agent, O₂ is an oxidizing agent.

Reactants:

• FeSO₄ – Iron(II) sulphate
  • Other names: Iron(II) sulfate , Ferrous sulfate , Green vitriol ... show moreIron vitriol , Copperas , Melanterite , Szomolnokite , Ferrous sulfate , Iron sulfate (1:1) , Iron(II) sulfate (1:1) , Ferrous sulfate (anhydrous) , Ferrous sulfate (anh.) , Iron(2+) sulfate (anh.) , FeSO4 , Fe(II)SO4 , Ferrous sulfate anhydrous show less
  • Appearance: White crystals (anhydrous) | White-yellow crystals (monohydrate) | Blue-green crystals (heptahydrate)
• NaOH
  • Names: Sodium hydroxide , Caustic soda , Lye ... show moreSoda lye , Sodium hydrate , NaOH , White caustic , Lye [Sodium hydroxide] show less
  • Appearance: White, waxy, opaque crystals ; White hygroscopic solid in various forms ; Colorless to white, odorless solid (flakes, beads, granular form).
• O₂
  • Names: Dioxygen , Oxygen , Oxygen (liquefied) ... show moreO2 , O₂ , Oxygen gas , Molecular oxygen , Oxygen, refrigerated liquid , LOX , Liquid oxygen show less
  • Appearance: Odourless compressed gas ; Liquefied gas. colourless-to-blue extremely cold liquid

Products:

• Fe₂O₃ – Iron(III) oxide
  • Other names: Ferric oxide , Hematite , Ferric iron ... show moreRed iron oxide , Rouge , Maghemite , Colcothar , Iron sesquioxide , Rust , Ochre , Iron oxide dust and fume (as Fe) , Iron oxide red , Red oxide , Anhydrous ferric oxide , Iron (III) oxide , Diiron trioxide , Iron trioxide , Ferric sesquioxide , Iron(III) oxide [Iron oxide dust and fume (as Fe)] , Iron(III)oxide [Rouge] show less
  • Appearance: Red-brown solid ; Reddish brown-to-black crystals or powder ; Reddish-brown solid. [Note: Exposure to fume may occur during the arc-welding of iron.] ; A fine, red powder of ferric oxide. [Note: Usually used in cake form or impregnated in paper or cloth.]
• Na₂SO₄
  • Names: Sodium sulfate , Sodium sulphate , Sulfate of sodium ... show moreThenardite (mineral) , Glauber's salt (decahydrate) , Sal mirabilis (decahydrate) , Mirabilite (decahydrate mineral) , Disodium sulfate , Anhydrous sodium sulfate , Sodium sulfate anhydrous , Sodium sulfate, anhydrous , Sodium sulphate anhydrous , Sodium sulphate, anhydrous , Sulfuric acid disodium salt, anhydrous , Disodium sulphate , Salt cake , Na2SO4 , Sulfuric acid disodium salt show less
  • Appearance: White crystalline solid | hygroscopic ; White hygroscopic solid in various forms
• H₂O – Water, oxidane
  • Other names: Water (H2O) , Hydrogen hydroxide (HH or HOH) , Hydrogen oxide ... show moreDihydrogen monoxide (DHMO) (systematic name) , Hydrogen monoxide , Dihydrogen oxide , Hydric acid , Hydrohydroxic acid , Hydroxic acid , Hydrol , Μ-oxido dihydrogen , Κ1-hydroxyl hydrogen(0) show less
  • Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas