Sun November 11, 2012 By: Abhijith C

Explain the preparation of Potassium pemanganate ?

Expert Reply
Mon November 12, 2012
When manganese dioxide is fused with potassium hydroxide in the presence of air or an oxidising agent such as potassium nitrate or chlorate, potassium manganate is formed, possibly via potassium manganite.
            MnO2 + 2KOH ––––––?    K2MnO3          +    4H2O] × 2
                                                              potassium manganite
            2K2MnO3 + O2 ––––––? 2K2MnO4 + 2H2O
            2MnO2 + 4KOH + O2 ––––––? 2K2MnO4 + 2H2O
            pyrolusite                                     potassium manganate
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