3 As2S3 + 4 HNO3 + 16 H2O → 6 H3AsO4 + 9 H2S + 4 NO
This is an oxidation-reduction (redox) reaction:
6 AsIII - 12 e- → 6 AsV (oxidation)
4 NV + 12 e- → 4 NII (reduction)
As2S3 is a reducing agent, HNO3 is an oxidizing agent.
Reactants:
- As2S3 – Arsenic trisulfide
- 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.]
- H2O – Water, oxidane
Products:
- H3AsO4 – Arsenic acid, arsoric acid
- H2S – Hydrogen sulfide
- Other names: D , Ihydrogen monosulfide|Dihydrogen sulfide|Sewer gas|Sulfane|Sulfurated hydrogen|Sulfureted hydrogen|Sulfuretted hydrogen|Sulfur hydride|Hydrosulfuric acid|Hydrothionic acid|Thiohydroxic acid|Sulfhydric acid}} , Hydrosulfuric acid
- Appearance: Colorless gas ; Colourless compressed liquefied gas with characteristic odour of rotten eggs ; Colorless gas with a strong odor of rotten eggs. [Note: Sense of smell becomes rapidly fatigued & can NOT be relied upon to warn of the continuous presence of H2S. Shipped as a liquefied compressed gas.]
- NO – Nitrogen monoxide , Oxidonitrogen(•) (additive)