5 H2O + 2 K2CrO4 + 3 K2SO3 → 3 K2SO4 + 4 KOH + 2 Cr(OH)3

This is an oxidation-reduction (redox) reaction:

3 SIV - 6 e- → 3 SVI (oxidation)

2 CrVI + 6 e- → 2 CrIII (reduction)

K2SO3 is a reducing agent, K2CrO4 is an oxidizing agent.

Reactants:

  • H2O – Water, oxidane source: wikipedia, accessed: 2019-09-27
    • Other names: Water (H2O) source: wikipedia, accessed: 2019-09-27, Hydrogen hydroxide (HH or HOH) source: wikipedia, accessed: 2019-09-27, Hydrogen oxide source: wikipedia, accessed: 2019-09-27
    • Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas source: wikipedia, accessed: 2019-09-27
  • K2CrO4 – Potassium chromate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Chromic acid source: wikipedia, accessed: 2019-09-27, (K2CrO4) source: wikipedia, accessed: 2019-09-27, Dipotassium salt source: wikipedia, accessed: 2019-09-27
    • Appearance: Yellow powder source: wikipedia, accessed: 2019-09-27; Yellow crystals source: ICSC, accessed: 2019-09-04
  • K2SO3 – Potassium sulfite source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Other names: E225 source: wikipedia, accessed: 2019-09-27, Potassium sulphite source: wikidata, accessed: 2019-09-02
    • Appearance: White solid source: wikipedia, accessed: 2019-09-27

Products:

  • K2SO4
    • Names: Potassium sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Potassium sulphate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Dipotassium sulfate source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Appearance: White solid source: wikipedia, accessed: 2019-09-27; Colourless-to-white crystals source: ICSC, accessed: 2019-09-04
  • KOH – Potassium hydroxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02
    • Other names: Caustic potash source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Lye source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Potash lye source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Appearance: White solid, deliquescent source: wikipedia, accessed: 2019-09-27; White hygroscopic solid in various forms source: ICSC, accessed: 2019-09-04; Odorless, white or slightly yellow lumps, rods, flakes, sticks, or pellets. [Note: May be used as an aqueous solution.] source: NIOSH NPG, accessed: 2019-09-02
  • Cr(OH)3 – Chromium(3+) hydroxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Other names: Chromium(III) hydroxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Chromium (iii) hydroxide hydrate source: ICSC, accessed: 2019-09-04, Cr(OH)3 source: wikidata, accessed: 2019-09-02, Chromic (III) hydroxide hydrate source: ICSC, accessed: 2019-09-04
    • Appearance: Green, gelatinous precipitate source: wikipedia, accessed: 2019-09-27; Blue-to-green powder or black particles source: ICSC, accessed: 2019-09-04