8 HNO3 (aq) + 3 H2S (g) → 3 H2SO4 (aq) + 8 NO (g) + 4 H2O (l)
This is an oxidation-reduction (redox) reaction:
3 S-II - 24 e- → 3 SVI (oxidation)
8 NV + 24 e- → 8 NII (reduction)
H2S is a reducing agent, HNO3 is an oxidizing agent.
Reactants:
- 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.]
- 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.]
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