4 Na2SO3 (aq) + 16 KI (aq) + 7 H2SO4 (aq) → 3 H2S (g) + 8 I2 (s) + 8 NaOH (aq) + 8 K2SO4 (aq)
This is an acid-base reaction (neutralization): Na2SO3 is a base, H2SO4 is an acid.
This is an oxidation-reduction (redox) reaction:
3 SIV + 18 e- → 3 S-II (reduction)
SIV - 2 e- → SVI (oxidation)
16 I-I - 16 e- → 16 I0 (oxidation)
Na2SO3 is an oxidizing agent, Na2SO3 is a reducing agent, KI is a reducing agent.
This is a precipitation reaction: I2 is the formed precipitate.
This is a gas evolution reaction, H2S is the formed gas.
Reactants:
Products:
- 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.]
- I2
- NaOH
- K2SO4