K2S2O8 (aq) + 2 KI (aq) I2 (s) + 2 K2SO4 (aq)

This is an oxidation-reduction (redox) reaction:

2 SVII + 2 e- 2 SVI (reduction)

2 I-I - 2 e- 2 I0 (oxidation)

K2S2O8 is an oxidizing agent, KI is a reducing agent.

This is a precipitation reaction: I2 is the formed precipitate.

Reactants:

  • K2S2O8
    • Names: Potassium persulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Potassium peroxydisulfate source: wikipedia, accessed: 2019-09-27source: ICSC, accessed: 2019-09-04, Anthion source: wikipedia, accessed: 2019-09-27
    • Appearance: White powder source: wikipedia, accessed: 2019-09-27; White crystals source: ICSC, accessed: 2019-09-04
  • KI
    • Names: Potassium iodide source: wikidata, accessed: 2019-09-02, KI source: wikidata, accessed: 2019-09-02, Thyrosafe source: wikidata, accessed: 2019-09-02

Products:

  • I2
    • Names: Iodine source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Jod source: ICSC, accessed: 2019-09-04, Iode source: ICSC, accessed: 2019-09-04
    • Appearance: Bluish black or dark purple crystals with pungent odour source: ICSC, accessed: 2019-09-04; Violet solid with a sharp, characteristic odor. source: NIOSH NPG, accessed: 2019-09-02
  • 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