Cr₂O₇^2- + 3 HNO₂ + 5 H⁺ → 2 (Cr)³⁺ + 3 NO₃^- + 4 H₂O

This is an oxidation-reduction (redox) reaction:

HNO₂ is a reducing agent, Cr₂O₇^2- is an oxidizing agent.

Reactants:

• Cr₂O₇^2-
• HNO₂ – Nitrous acid , Hydroxidooxidonitrogen
  • Other names: HNO2 , [NO(OH)] , Nitrosyl hydroxide , Dioxonitric acid
  • Appearance: Pale blue solution
• H⁺

Products:

• Cr³⁺
• NO₃^- – Nitrate
  • Other names: Nitrate ion , NO3(-) , [NO3](-) ... show moreNitrate(1-) , NO3 , Trioxonitrate , Isosorbide Dinitrate , Gynazole-1 , Nitric acid , Sorbitrate , Trioxidonitrate , Ganite , Econazole Nitrate , Femstat 3 , Isordil , Nitrooxidane show less
• 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