4 Zn (s) + Na2S2O3 (aq) + 10 HCl (aq) → 4 ZnCl2 (aq) + 2 H2S (g) + 2 NaCl (aq) + 3 H2O (l)
This is an oxidation-reduction (redox) reaction:
2 SII + 8 e- → 2 S-II (reduction)
4 Zn0 - 8 e- → 4 ZnII (oxidation)
Na2S2O3 is an oxidizing agent, Zn is a reducing agent.
Reactants:
- Zn
- Na2S2O3
- HCl – Chlorane , Hydrogen chloride
- Other names: Hydrochloric acid , M , Uriatic acid
- Appearance: Colorless, transparent liquid, fumes in air if concentrated ; Colorless gas ; Colourless compressed liquefied gas with pungent odour ; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.]
Products:
- ZnCl2 – Zinc chloride
- 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.]
- NaCl – Sodium chloride
- H2O – Water, oxidane