Cr2O3 (s) + 2 Na2CO3 (aq) + 3 KNO3 (aq) → 2 Na2CrO4 (aq) + 2 CO2 (g) + 3 KNO2 (aq)

This is an oxidation-reduction (redox) reaction:

3 NV + 6 e- → 3 NIII (reduction)

2 CrIII - 6 e- → 2 CrVI (oxidation)

KNO3 is an oxidizing agent, Cr2O3 is a reducing agent.

Reactants:

  • 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
  • Na2CO3 – Sodium carbonate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Other names: Soda ash source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Washing soda source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Soda crystals source: wikipedia, accessed: 2019-09-27
    • Appearance: White solid, hygroscopic source: wikipedia, accessed: 2019-09-27; White hygroscopic powder source: ICSC, accessed: 2019-09-04
  • KNO3 – Potassium nitrate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04
    • Other names: Saltpeter source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Saltpetre source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02, Nitrate of potash source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Appearance: White solid source: wikipedia, accessed: 2019-09-27; Colourless-to-white crystalline powder source: ICSC, accessed: 2019-09-04

Products:

  • Na2CrO4 – Sodium 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, (Na2CrO4) source: wikipedia, accessed: 2019-09-27, Disodium salt source: wikipedia, accessed: 2019-09-27
    • Appearance: Yellow crystals source: wikipedia, accessed: 2019-09-27; Yellow hygroscopic crystals source: ICSC, accessed: 2019-09-04
  • CO2
    • Names: Carbon dioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, {{plainlist| source: wikipedia, accessed: 2019-09-27, CO2 source: wikidata, accessed: 2019-09-02
    • Appearance: Colorless gas source: wikipedia, accessed: 2019-09-27; Odourless colourless compressed liquefied gas source: ICSC, accessed: 2019-09-04; Colorless, odorless gas. [Note: Shipped as a liquefied compressed gas. Solid form is utilized as dry ice.] source: NIOSH NPG, accessed: 2019-09-02
  • KNO2
    • Names: Potassium nitrite source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Nitrous acid potassium salt source: ICSC, accessed: 2019-09-04
    • Appearance: White or slight yellow solid | deliquescent source: wikipedia, accessed: 2019-09-27; White-to-yellow deliquescent solid in various forms source: ICSC, accessed: 2019-09-04