Why dilute H2SO4 is the most suitable as compared to HCl and HNO3 in potassium
permanganate titration?
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HNO3 is also a powerful oxidizing agent along with KMnO4 so it also plays its role in oxidation which causes a decline in the value of KMNo4 used. As dilute sulfuric acid is ideal for redox titration because it is neither an oxidizing agent and nor a reducing agent.
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Titrations involving potassium permanganate are usually carried out in acidic medium. This is due to higher oxidizing power of permanganate ion in acidic medium than in neutral or basic medium.
Secondly, the formation of brown coloured MnO2 in basic medium interferes with the detection of the end point. For acidification of KMnO4 solution, only H2SO4 is suitable whereas the other mineral acids like HCl and HNO3 are not. HCl is not used because some of the KMnO4 will oxidize chloride ions to chlorine gas.
Nitric acid cannot be used because it is itself a strong oxidizing agent and may oxidize the reducing agent, thereby introducing error in the analysis.
Secondly, the formation of brown coloured MnO2 in basic medium interferes with the detection of the end point. For acidification of KMnO4 solution, only H2SO4 is suitable whereas the other mineral acids like HCl and HNO3 are not. HCl is not used because some of the KMnO4 will oxidize chloride ions to chlorine gas.
Nitric acid cannot be used because it is itself a strong oxidizing agent and may oxidize the reducing agent, thereby introducing error in the analysis.
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