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Permanganate
From Wikipedia, the free encyclopedia
A permanganate is a chemical compound that contains the permanganate ion (MnO4−). Because manganese is in the +7 oxidation state, the permanganate ion is a strong oxidizer.
In an acidic solution, permanganate will reduce to the clear +2 oxidation state of the Manganese(II) (Mn2+) ion.
- 16 H3O + + 2 MnO4− + 10 Cl− → 2 Mn2+ + 5 Cl2 + 24 H2O
- 6 H+ + 2 MnO4− + 5 HCOOH → 8 H2O + 2 Mn2+ + 5 CO2
In a basic solution, permanganate will either reduce to the brown +4 oxidation state of MnO2 or to the green +6 oxidation state of MnO42−.
- 4 OH− + 2 MnO4− + 3 C2O42− → 2 MnO2 + 6 CO32− + 2 H2O
- 3 OH− + 2 MnO4− + HSO3− → 2 MnO42− + SO42− + 2 H2O
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Permanganates may be produced by oxidization of manganese compounds by strong oxidizing agents, for instance, sodium hypochlorite or lead dioxide:
- 2 MnCl2 + 5 NaClO + 6 NaOH → 2 NaMnO4 + 9 NaCl+ 3 H2O
- 2 MnSO4 + 5 PbO2+ 3 H2SO4 → 2 HMnO4+ 5 PbSO4 + 2 H2O
Or by dismutation of manganates:
Permanganates are salts of permanganic acid. Permanganate is a strong oxidizer, and similar to perchlorate. Being a strong oxidiser it is in common use in qualitative analysis experiments involving redox reactions(permanganometry).Besides this, it is stable.
It is a useful reagent, though with organic compounds, it may just destroy them entirely.
Permanganates are not very thermically stable. For instance, potassium permanganate decomposes at 230 °C:
- Potassium permanganate, KMnO4
- Sodium permanganate, NaMnO4
See category for a bigger list.
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