Fe3O4 + 8 HCl → FeCl2 + 2 FeCl3 + 4 H2O - Balanced Equation

This is an acid-base reaction (neutralization): Fe3O4 is a base, HCl is an acid.

This is an oxidation-reduction (redox) reaction:

Fe8/3+2/3e-→FeII(reduction)

2Fe8/3-2/3e-→2FeIII(oxidation)

Fe3O4 is both an oxidizing and a reducing agent (disproportionation (dismutation)).

Reactants:

• Fe3O4 – Iron(II) iron(III) oxide
  • Other names: Iron(II,III) oxide , Ferrous ferric oxide , Ferroso ferric oxide ... show moreIron(II , III) oxide , Magnetite , Black iron oxide , Lodestone , Rust , Iron(II) diiron(III) oxide , Ferro ferric oxide , Ferric ferrous oxide , Ferrosoferric oxide , Triiron tetraoxide show less
  • Appearance: Solid black powder
• HCl – Chlorane , Hydrogen chloride
  • Other names: Hydrochloric acid , M , Uriatic acid ... show moreHydronium chloride , Chlorhydric Acid , Hydrochloric acid gas , HCl , Anhydrous hydrogen chloride , Hydrochloric acid, anhydrous , Aqueous hydrogen chloride , [Note: Often used in an aqueous solution.] show less
  • Appearance: Colorless, transparent liquid, fumes in air if concentrated ; Colorless gas ; Colourless compressed liquefied gas with pungent odour ; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.]

Products:

• FeCl2 – Iron(II) chloride , Iron dichloride
  • Other names: Ferrous chloride , Rokühnite , [FeCl3] , FeCl3
  • Appearance: Tan solid (anhydrous) | Pale green solid (di-tetrahydrate) ; White-to-light-green hygroscopic crystals
• FeCl3 – Iron(III) chloride , Iron trichloride
  • Other names: {{ubl , Ferric chloride , Ferric chloride (anhydrous) ... show moreIron(3+);trichloride , Ferric;trichloride , [FeCl3] , FeCl3 , Iron chloride , Flores martis , Molysite show less
  • Appearance: Green-black by reflected light; purple-red by transmitted light; yellow solid as hexahydrate; brown as {{abbr|aq.|aqueous}} solution ; Black-to-brown hygroscopic crystals
• 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