4 HNO₃ + 3 FeCl₂ → 2 H₂O + NO + 2 FeCl₃ + Fe(NO₃)₃

This is an oxidation-reduction (redox) reaction:

HNO₃ is an oxidizing agent, FeCl₂ is a reducing agent.

Reactants:

• HNO₃ – Nitric acid
  • Other names: Aqua fortis , Spirit of niter , Eau forte ... show moreHydrogen nitrate , Acidum nitricum , Nitric acid (> 70% in water) , Fuming nitric acid , Engravers acid , HONO2 , Red fuming nitric acid , RFNA , White fuming nitric acid (WFNA) show less
  • 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.]
• 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

Products:

• 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
• NO – Nitrogen monoxide , Oxidonitrogen(•) (additive)
  • Other names: Nitric oxide , Nitrogen(II) oxide , Nitric oxide (radical) ... show moreMononitrogen monoxide , (.)NO , EDRF , Nitrogen monooxide , [NO] , Oxido de nitrogeno(ii) , NO(.) , Oxido nitrico , Stickstoff(ii)-oxid , NO , Oxyde azotique , Oxyde nitrique , Stickstoffmonoxid , Nitrosyl , (NO)(.) , Monoxido de nitrogeno , Endothelium-derived relaxing factor , Nitroxide radical , Nitroxyl , Nitrosyl radical , Hydroxyamine , Nitrogen oxide , Nitrogen protoxide , Nitrosyl hydride , Nitric Oxide show less
  • Appearance: Colourless gas ; Colourless compressed gas ; Colorless gas. [Note: Shipped as a nonliquefied compressed gas.]
• 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
• Fe(NO₃)₃ – Iron(III) nitrate
  • Other names: Ferric nitrate , Nitric acid , Iron(3+) salt , Iron (III) nitrate
  • Appearance: Pale violet crystals | hygroscopic