2 Cr2O72- + 2 H+ + 3 S → 3 SO2 + 2 OH- + 2 Cr2O3
This is an oxidation-reduction (redox) reaction:
3 S0 - 12 e- → 3 SIV (oxidation)
4 CrVI + 12 e- → 4 CrIII (reduction)
S is a reducing agent, Cr2O72- is an oxidizing agent.
Reactants:
Products:
- SO2 – Sulfur dioxide
- Other names: Sulfurous anhydride , Sulphur dioxide , Sulfurous acid anhydride
- Appearance: Colorless gas ; Colourless gas or compressed liquefied gas with pungent odour ; Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14°F. Shipped as a liquefied compressed gas.]
- OH- – Hydroxide
- Cr2O3