Question:
Potassium permanganate ($KMnO_{4}$) is called a self-indicator because:
Potassium permanganate ($KMnO_{4}$) is called a self-indicator because:
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No extra indicator needed for Permanganate; the purple color does the job.
Updated On: May 25, 2026
- It forms a precipitate during titration
- It shows purple colour at the end point
- It works with starch indicator
- It is colourless
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The Correct Option is B
Solution and Explanation
Step 1: Concept
In redox titrations, some reagents possess a strong inherent color that changes or persists at the equivalence point.
Step 2: Meaning
A self-indicator eliminates the need for an external chemical indicator like phenolphthalein or methyl orange.
Step 3: Analysis
$KMnO_{4}$ is a deep purple solution. During titration, it is reduced to colorless $Mn^{2+}$. Once the analyte is exhausted, the first excess drop of $KMnO_{4}$ imparts a persistent pink/purple color to the solution.
Step 4: Conclusion
This visible color change at the end point allows $KMnO_{4}$ to function as its own indicator. Final Answer: (B)
In redox titrations, some reagents possess a strong inherent color that changes or persists at the equivalence point.
Step 2: Meaning
A self-indicator eliminates the need for an external chemical indicator like phenolphthalein or methyl orange.
Step 3: Analysis
$KMnO_{4}$ is a deep purple solution. During titration, it is reduced to colorless $Mn^{2+}$. Once the analyte is exhausted, the first excess drop of $KMnO_{4}$ imparts a persistent pink/purple color to the solution.
Step 4: Conclusion
This visible color change at the end point allows $KMnO_{4}$ to function as its own indicator. Final Answer: (B)
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