Na2S (aq) + I2 (s) → 2 NaI (aq) + S (s)

This is an oxidation-reduction (redox) reaction:

S-II - 2 e- → S0 (oxidation)

2 I0 + 2 e- → 2 I-I (reduction)

Na2S is a reducing agent, I2 is an oxidizing agent.

Reactants:

  • Na2S
    • Names: Sodium sulfide source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02, Disodium sulfide source: wikipedia, accessed: 2019-09-28source: wikidata, accessed: 2019-09-02, Sodium sulfide (anhydrous) source: ICSC, accessed: 2019-09-04
    • Appearance: Colorless, hygroscopic solid source: wikipedia, accessed: 2019-09-28; White-to-yellow hygroscopic crystals with characteristic odour source: ICSC, accessed: 2019-09-04
  • 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

Products:

  • NaI
    • Names: Sodium iodide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Sodium iodide (anhydrous) source: ICSC, accessed: 2019-09-04, NaI source: wikidata, accessed: 2019-09-02, Sodium monoiodide source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Appearance: White solid | deliquescent source: wikipedia, accessed: 2019-09-27; Colourless-to-white hygroscopic crystals or white powder. turns brown on exposure to air source: ICSC, accessed: 2019-09-04
  • S
    • Names: Sulfur source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04, S source: wikidata, accessed: 2019-09-07, Sulphur source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04
    • Appearance: Yellow solid in various forms source: ICSC, accessed: 2019-09-04