3 SO2 (aq) + 2 Al(OH)3 (s) → 3 H2 (g) + Al2(SO4)3 (aq)

This is an acid-base reaction (neutralization): SO2 is an acid, Al(OH)3 is a base.

This is an oxidation-reduction (redox) reaction:

3 SIV - 6 e- → 3 SVI (oxidation)

6 HI + 6 e- → 6 H0 (reduction)

SO2 is a reducing agent, Al(OH)3 is an oxidizing agent.

Reactants:

  • SO2 – Sulfur dioxide source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Sulfurous anhydride source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Sulphur dioxide source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-02, Sulfurous acid anhydride source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02
    • Appearance: Colorless gas source: wikipedia, accessed: 2019-09-28; Colourless gas or compressed liquefied gas with pungent odour source: ICSC, accessed: 2019-09-04; Colorless gas with a characteristic, irritating, pungent odor. [Note: A liquid below 14°F. Shipped as a liquefied compressed gas.] source: NIOSH NPG, accessed: 2019-09-02
  • Al(OH)3 – Aluminium hydroxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Aluminium(3+) trioxidanide source: wikipedia, accessed: 2019-09-27
    • Other names: Aluminic acid source: wikipedia, accessed: 2019-09-27, Aluminum hydroxide source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Al(OH)3 source: wikidata, accessed: 2019-09-02
    • Appearance: White amorphous powder source: wikipedia, accessed: 2019-09-27; Odourless white solid in various forms source: ICSC, accessed: 2019-09-04

Products:

  • H2
    • Names: Dihydrogen source: wikidata, accessed: 2019-09-07, Hydrogen source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-07, H2 source: wikidata, accessed: 2019-09-07
    • Appearance: Odourless colourless compressed gas source: ICSC, accessed: 2019-09-04
  • Al2(SO4)3 – Aluminium sulfate source: wikipedia, accessed: 2019-09-27source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-02
    • Other names: Aluminum sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Aluminium sulphate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Cake alum source: wikipedia, accessed: 2019-09-27
    • Appearance: White crystalline solid | hygroscopic source: wikipedia, accessed: 2019-09-27; Odourless white hygroscopic lustrous crystals or powder source: ICSC, accessed: 2019-09-04