Potassium permanganate (KMnO4) is a versatile and powerful oxidant. It can be used direct or indirect to classify many different substances. The unique property of potassium permanganate is that it acts as a self-indicator in redox titrations.
KMnO4 is intense purple, when used in redox titration it is reduced to brown Mn2+ ion (in acidic conditions) at the endpoint, and the color transition at the endpoint can be quickly observed. The titration of potassium permanganate against oxalic acid is an example of redox titration.
Why KMnO4 is a self indicator?
KMnO4 is always in a stable form. In an acidic condition, KMnO4 undergoes reduction from Mn2 +. As a result, the color of the solution changes from pink to brown. Once KMnO4 starts to react in a chemical reaction, no separate indicator for permanganate titration is required. Due to color changes, we will observe the indication. Therefore, KMnO4 is a self-indicator in analysis.
A self-indicator is a chemical compound that itself indicates the endpoint of the titration. The discussion above leads us to the conclusion that KMnO4 is a self-indicator.
Frequently Asked Question (FAQ):
Why is potassium dichromate not a self-indicator?
Since potassium dichromate (k2cr2o7) acts as an oxidizing agent only in acidic conditions, it cannot be used as a self-indicator since its reduction product blocks itself during visual detection at the end of the reaction.
In which titration is KMnO4 used as a self-indicator?
KMnO4 is used as a self-indicator in redox titration to detect the endpoint. Redox titration is performed to identify the oxidizing or reducing agents in a solution. In redox titration, either the reducing or oxidizing agent will be employed as the titrant against the other agent.
Is permanganate a self-indicator?
Yes, permanganate is a self-indicator. Solutions of KMnO4 are dark purple. When employed as a titrant, once the endpoint is reached and the KMnO4- is in excess, the solution has a permanent pink color when employed as a titrant (provided that the solution is initially colorless). KMnO4 serves as its self indicator as a result.
Why is KMnO4 strong oxidizing agent?
KMnO4 is a strong oxidizing agent since the main metal atom (Mn) in KMnO4 is in an extremely high +7 oxidation state, meaning it has lost all of its valence electrons. As a result, KMnO4 is a potent oxidizing agent.
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