3 H3PO3 + 2 HNO3 → 2 NO + 3 H3PO4 + H2O
This is an oxidation-reduction (redox) reaction:
3 PIII - 6 e- → 3 PV (oxidation)
2 NV + 6 e- → 2 NII (reduction)
H3PO3 is a reducing agent, HNO3 is an oxidizing agent.
Reactants:
- H3PO3 – Phosphonic acid
- 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.]
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