Qualitative analysis of  Manganese II ions

Qualitative analysis of  Manganese II ions

Addition of dilute sodium hydroxide  of ammonia solution drop wise until in excess.

A white ppt. insoluble in excess, rapidly turning brown.

Mn²⁺ (aq) + 2^–OH (aq)  → Mn(OH)₂ (s)

Then

4Mn(OH)₂ (s)  + O₂(g) →    Mn₂O₃(s) + 2H₂O(l)

 Confirmatory test of Mn²⁺

Mn²⁺ aqueous solution turn purple solution on addition concentrated nitric acid followed by sodium bismuthate or Lead (IV) oxide.

2Mn²⁺ (aq) + 5BiO₃^– (s) + 14H⁺ (aq) → 2MnO₄^– (aq) + 5Bi³⁺ (aq) + 7H₂O (l)

2Mn²⁺ (aq) + 5PbO₂(s) + 4H⁺ (aq) → 2MnO₄^– (aq) + 5Pb²⁺ (aq) + 2H₂O (l)

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