Permanganometric Analysis

Definition Permanganometric

     Permanganometric is one of the quantitative volumetric analysis based on the reaction of permanganate ion oxidation.
Standard solution used is KMnO4. Before used for titration, a solution of KMnO4 must be standardized in advance because not a primary standard solution. Additionally KMnO4 has the following characteristics:
1. Can not be obtained in pure
2. Containing oxides MnO and Mn2O3
3. The solution is not stable (if any organic substance) 

Reaction:

4     MnO₄^- + 2 H₂O → 4 MnO₂ + 3 O₂ + 4 OH^-

4. It should not be filtered with filter paper (organic matter) →with glass wool
5. Should be stored in brown bottles
6. Standardized with primary standard solution. Primary standard substance which is used such as: As₂O₃, Na₂C₂O₄, H₂C₂O₄, Fe(NH₄)₂(SO₄)₂, K₄Fe(CN)₆, logam Fe, KHC₂O₄H₂C₂O₄2H₂O

      Permanganate ion oxidation can take place under acidic, neutral and alkaline. 

In acidic conditions, pH ± 1
Reaction: MnO ^-+ 8 H⁺+ 5 e → Mn²⁺+ 4 H₂O 

       Potassium permanganate can act as an indicator, and titration is generally done in the sour atmosphere because it will be easier to observe the end point titration. But there are some compounds more easily oxidized in an atmosphere of neutral or alkaline example hydrazine, sulfite, sulfide, sulfide and thiosulfate. 

      Reaction in the neutral atmosphere:

      MnO ^- + 4 H⁺+ 3 e → MnO₂ + 2 H₂O

      Reactions in the atmosphere of alkalis or bases :

MnO ^-+ 3e → MnO₄^2-

MnO ^2-+ 2H₂O + 2e → MnO₂ + 4OH^-

MnO ^-+ 2H₂O + 3e → MnO₂ + 4OH^-

Advantages and Disadvantages Analysis with Permanganometri

- The advantages
1. Standard solution, namely KMnO4 easily available and cheap.
2. No need for indicators to TAT. That's because KMnO4 can act as an indicator.
3. The reaction was fast with lots of reagents.
            - Disadvantages
1. There should be standardization of the initial advance.
2. Can take better if done in acidic conditions.
3. The time required for analysis is quite long.

credits: Book of PDTK 1 2011 Chemical Engineering of Diponegoro University