3 HNO3 (aq) + Cr2O3 (s) + 7 KOH (aq) → 3 KNO2 (aq) + 2 K2CrO4 (aq) + 5 H2O (l)
This is an acid-base reaction (neutralization): HNO3 is an acid, KOH is a base.
This is an oxidation-reduction (redox) reaction:
3 NV + 6 e- → 3 NIII (reduction)
2 CrIII - 6 e- → 2 CrVI (oxidation)
HNO3 is an oxidizing agent, Cr2O3 is a reducing agent.
- 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.]
- KOH – Potassium hydroxide
- K2CrO4 – Potassium chromate
- H2O – Water, oxidane