4 CaI2 (aq) + 5 H2SO4 (aq) → 4 CaSO4 (s) + H2S (g) + 4 I2 (s) + 4 H2O (l)
This is an oxidation-reduction (redox) reaction:
SVI + 8 e- → S-II (reduction)
8 I-I - 8 e- → 8 I0 (oxidation)
H2SO4 is an oxidizing agent, CaI2 is a reducing agent.
This is a precipitation reaction: CaSO4 andI2 is the formed precipitate.
This is a gas evolution reaction, H2S is the formed gas.
- CaI2 – Calcium iodide
- H2SO4 – Sulfuric acid
- H2S – Hydrogen sulfide
- Other names: Dihydrogen monosulfide , Dihydrogen sulfide , Sewer gas
- 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.]
- H2O – Water, oxidane