8 HNO3 + K2Cr2O4 + 2 Fe(NO3)2 → 2 KNO3 + 2 Fe(NO3)3 + 2 Cr(NO3)2 + 4 H2O

This is an oxidation-reduction (redox) reaction:

4 NV + 8 e- → 4 NIII (reduction)

2 CrIII - 6 e- → 2 CrVI (oxidation)

2 FeII - 2 e- → 2 FeIII (oxidation)

Reactants:

  • HNO3 – Nitric acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Aqua fortis source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02, Spirit of niter source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Eau forte source: wikipedia, accessed: 2019-09-27
    • Appearance: Colorless, yellow or red fuming liquid source: wikipedia, accessed: 2019-09-27; Colourless-to-yellow liquid with pungent odour source: ICSC, accessed: 2019-09-04; 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.] source: NIOSH NPG, accessed: 2019-09-02
  • K2Cr2O4
  • Fe(NO3)2

Products:

  • KNO3 – Potassium nitrate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Saltpeter source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Saltpetre source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Nitrate of potash source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Appearance: White solid source: wikipedia, accessed: 2019-09-27; Colourless-to-white crystalline powder source: ICSC, accessed: 2019-09-04
  • Fe(NO3)3 – Iron(III) nitrate source: wikipedia, accessed: 2019-09-27
    • Other names: Ferric nitrate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Nitric acid source: wikipedia, accessed: 2019-09-27, Iron(3+) salt source: wikipedia, accessed: 2019-09-27, Iron (III) nitrate source: wikidata, accessed: 2019-09-02
    • Appearance: Pale violet crystals | hygroscopic source: wikipedia, accessed: 2019-09-27
  • Cr(NO3)2
    • H2O – Water, oxidane source: wikipedia, accessed: 2019-09-27
      • Other names: Water (H2O) source: wikipedia, accessed: 2019-09-27, Hydrogen hydroxide (HH or HOH) source: wikipedia, accessed: 2019-09-27, Hydrogen oxide source: wikipedia, accessed: 2019-09-27
      • Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas source: wikipedia, accessed: 2019-09-27