As2O3 + 2 HNO3 + 2 H2O → 2 H3AsO4 + N2O3

This is an oxidation-reduction (redox) reaction:

2 AsIII - 4 e- → 2 AsV (oxidation)

2 NV + 4 e- → 2 NIII (reduction)

As2O3 is a reducing agent, HNO3 is an oxidizing agent.

Reactants:

  • As2O3 – Diarsenic trioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Arsenic trioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Arsenic(III) oxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Arsenic sesquioxide source: wikipedia, accessed: 2019-09-27
    • Appearance: White solid source: wikipedia, accessed: 2019-09-27; White lumps or crystalline powder source: ICSC, accessed: 2019-09-04
  • HNO3 – Nitric acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Aqua fortis source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02, Spirit of niter source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Eau forte source: wikipedia, accessed: 2019-09-27
    • Appearance: Colorless, yellow or red fuming liquid source: wikipedia, accessed: 2019-09-27; Colourless-to-yellow liquid with pungent odour source: ICSC, accessed: 2019-09-04; 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.] source: NIOSH NPG, accessed: 2019-09-02
  • H2O – Water, oxidane source: wikipedia, accessed: 2019-09-27
    • Other names: Water (H2O) source: wikipedia, accessed: 2019-09-27, Hydrogen hydroxide (HH or HOH) source: wikipedia, accessed: 2019-09-27, Hydrogen oxide source: wikipedia, accessed: 2019-09-27
    • Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas source: wikipedia, accessed: 2019-09-27

Products:

  • H3AsO4 – Arsenic acid, arsoric acid source: wikipedia, accessed: 2019-09-27
    • Other names: Arsenic acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Orthoarsenic acid source: wikipedia, accessed: 2019-09-27, Desiccant L-10 source: wikipedia, accessed: 2019-09-27
    • Appearance: White translucent crystals | hygroscopic. source: wikipedia, accessed: 2019-09-27; Colourless-to-pale-green-viscous liquid source: ICSC, accessed: 2019-09-04
  • N2O3
    • Names: Dinitrogen trioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Nitrous anhydride source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Nitrogen sesquioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Appearance: Deep blue tinted gas source: wikipedia, accessed: 2019-09-27