As2S5 + 20 Cl2 + 28 H2O → 2 H3AsO4 + 5 H2SO4 + 40 HCl

This is an oxidation-reduction (redox) reaction:

5 S-II - 40 e- → 5 SVI (oxidation)

40 Cl0 + 40 e- → 40 Cl-I (reduction)

As2S5 is a reducing agent, Cl2 is an oxidizing agent.

Reactants:

  • As2S5 – Arsenic pentasulfide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Other names: Arsenic(V) sulfide source: wikipedia, accessed: 2019-09-27, Diarsenic pentasulfide source: wikidata, accessed: 2019-09-02
    • Appearance: Vivid, dark orange, opaque crystals source: wikipedia, accessed: 2019-09-27
  • Cl2
    • Names: Chlorine source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Molecular chlorine source: NIOSH NPG, accessed: 2019-09-02
    • Appearance: Greenish-yellow compressed liquefied gas with pungent odour source: ICSC, accessed: 2019-09-04; Greenish-yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.] 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
  • H2SO4 – Sulfuric acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Oil of vitriol source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Sulfuric acid, concentrated (> 51% and < 100%) source: ICSC, accessed: 2019-09-04, H2SO4 source: wikidata, accessed: 2019-09-07
    • Appearance: Clear, colorless liquid source: wikipedia, accessed: 2019-09-27; Odourless colourless oily hygroscopic liquid source: ICSC, accessed: 2019-09-04; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.] source: NIOSH NPG, accessed: 2019-09-02
  • HCl – Chlorane source: wikipedia, accessed: 2019-09-27, Hydrogen chloride source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Hydrochloric acid source: wikipedia, accessed: 2019-09-27source: NIOSH NPG, accessed: 2019-09-02, M source: wikipedia, accessed: 2019-09-27, Uriatic acid source: wikipedia, accessed: 2019-09-27
    • Appearance: Colorless, transparent liquid, fumes in air if concentrated source: wikipedia, accessed: 2019-09-27; Colorless gas source: wikipedia, accessed: 2019-09-27; Colourless compressed liquefied gas with pungent odour source: ICSC, accessed: 2019-09-04; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.] source: NIOSH NPG, accessed: 2019-09-02