4 HNO3 (aq) → 4 NO2 (l) + 2 H2O (l) + O2 (g)
This is an oxidation-reduction (redox) reaction:
4 NV + 4 e- → 4 NIV (reduction)
2 O-II - 4 e- → 2 O0 (oxidation)
HNO3 is an oxidizing agent, HNO3 is a reducing agent.
This is a gas evolution reaction, O2 is the formed gas.
- 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.]
- NO2 – Nitrogen dioxide
- Other names: Nitrogen(IV) oxide , Deutoxide of nitrogen , Nitrogen peroxide
- Appearance: Brown gas ; Reddish-brown gas or brown or yellow liquid with pungent odour ; Yellowish-brown liquid or reddish-brown gas (above 70°F) with a pungent, acrid odor. [Note: In solid form (below 15°F) it is found structurally as N2O4.]
- H2O – Water, oxidane