3 Fe3O4 + 28 HNO3 → 9 Fe(NO3)3 + NO + 14 H2O

This is an acid-base reaction (neutralization): Fe₃O₄ is a base, HNO₃ is an acid.

This is an oxidation-reduction (redox) reaction:

N^V + 3 e^- → N^II (reduction)

9 Fe^8/3 - 3 e^- → 9 Fe^III (oxidation)

HNO₃ is an oxidizing agent, Fe₃O₄ is a reducing agent.

Reactants:

Fe₃O₄ – Iron(II) iron(III) oxide
- Other names: Iron(II,III) oxide , Ferrous ferric oxide , Ferroso ferric oxide
- Appearance: Solid thâm powder
HNO₃ – Nitric acid
- Other names: Aqua fortis , Spirit of niter , Eau forte
- Appearance: Colorless, yellow or red fuming liquid ; Colourless-to-yellow liquid with pungent odour ; Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]

Products:

Fe(NO₃)₃ – Iron(III) nitrate
- Other names: Ferric nitrate , Nitric acid , Iron(3+) salt , Iron (III) nitrate
- Appearance: Pale violet crystals | hygroscopic
NO – Nitrogen monoxide , Oxidonitrogen(•) (additive)
- Other names: Nitric oxide , Nitrogen(II) oxide , Nitric oxide (radical)
- Appearance: Colourless gas ; Colourless compressed gas ; Colorless gas. [Note: Shipped as a nonliquefied compressed gas.]
H₂O – Water, oxidane
- Other names: Water (H2O) , Hydrogen hydroxide (HH or HOH) , Hydrogen oxide
- Appearance: White crystalline solid, almost colorless liquid with a hint of xanh lơ, colorless gas