2 (NH4)2Cr2O7 (aq) 2 Cr2O3 (s) + 4 NH3 (aq) + 3 O2 (g) + 2 H2O (l)

This is an oxidation-reduction (redox) reaction:

4 CrVI + 12 e- 4 CrIII (reduction)

6 O-II - 12 e- 6 O0 (oxidation)

(NH4)2Cr2O7 is an oxidizing agent, (NH4)2Cr2O7 is a reducing agent.

This is a precipitation reaction: Cr2O3 is the formed precipitate.

This is a gas evolution reaction, O2 is the formed gas.

Reactants:

  • (NH4)2Cr2O7Ammonium dichromate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Ammonium bichromate source: wikipedia, accessed: 2019-09-27source: ICSC, accessed: 2019-09-04, Ammonium pyrochromate source: wikipedia, accessed: 2019-09-27, Diammonium dichromate (VI) source: ICSC, accessed: 2019-09-04, Dichromic acid, diammonium salt source: ICSC, accessed: 2019-09-04
    • Appearance: Orange-red crystals source: wikipedia, accessed: 2019-09-27; Orange-to-red crystals source: ICSC, accessed: 2019-09-04

Products:

  • Cr2O3
    • Names: Chromium(III) oxide source: wikipedia, accessed: 2019-09-27, Chromium sesquioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Chromia source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Appearance: Light to dark green, fine crystals source: wikipedia, accessed: 2019-09-27; Light-to-dark-green powder source: ICSC, accessed: 2019-09-04
  • NH3
    • Names: Ammonia source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: NIOSH NPG, accessed: 2019-09-02, Azane (only intended for use in naming derivatives of ammonia) source: wikipedia, accessed: 2019-09-27, Hydrogen nitride source: wikipedia, accessed: 2019-09-27
    • Appearance: Colourless gas source: wikipedia, accessed: 2019-09-27; Colourless gas or compressed liquefied gas with pungent odour source: ICSC, accessed: 2019-09-04; Colorless gas with a pungent, suffocating odor. [Note: Shipped as a liquefied compressed gas. Easily liquefied under pressure.] source: NIOSH NPG, accessed: 2019-09-02
  • O2
    • Names: Dioxygen source: wikidata, accessed: 2019-09-07, Oxygen source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-07, Oxygen (liquefied) source: ICSC, accessed: 2019-09-04
    • Appearance: Odourless compressed gas source: ICSC, accessed: 2019-09-04; Liquefied gas. colourless-to-blue extremely cold liquid source: ICSC, accessed: 2019-09-04
  • H2OWater, 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