Cr2O72- + 2 H+ + 3 (Mn)2+ → 2 (Cr)3+ + 3 MnO2 + H2O

This is an oxidation-reduction (redox) reaction:

3 MnII - 6 e- → 3 MnIV (oxidation)

2 CrVI + 6 e- → 2 CrIII (reduction)

Mn2+ is a reducing agent, Cr2O72- is an oxidizing agent.

Reactants:

  • Cr2O72-
  • H+
  • Mn2+

Products:

  • Cr3+
  • MnO2 – Manganese oxide source: wikipedia, accessed: 2019-09-27, Manganese(IV) oxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02
    • Other names: Manganese dioxide source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04, Pyrolusite source: wikipedia, accessed: 2019-09-27, Hyperoxide of manganese source: wikipedia, accessed: 2019-09-27
    • Appearance: Brown-black solid source: wikipedia, accessed: 2019-09-27; Black-to-brown powder source: ICSC, accessed: 2019-09-04
  • 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