2 HNO3 (aq) + Na2SO3 (aq) → H2O (l) + Na2SO4 (aq) + 2 NO2 (l)
This is an acid-base reaction (neutralization): HNO3 is an acid, Na2SO3 is a base.
This is an oxidation-reduction (redox) reaction:
SIV - 2 e- → SVI (oxidation)
2 NV + 2 e- → 2 NIV (reduction)
Na2SO3 is a reducing agent, HNO3 is an oxidizing 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.]
- Na2SO3 – Sodium sulfite
- H2O – Water, oxidane
- 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.]