Which Indicator Is a Self-Indicator?

Potassium permanganate (KMnO₄) is the most common self-indicator, along with iodine and potassium dichromate in specific titrations.

Primary Self-Indicators:

1. Potassium Permanganate (KMnO₄):

• Purple to colorless (or persistent pink at endpoint)
• Used in redox titrations
• Most widely recognized self-indicator

2. Iodine (I₂):

• Brown color in solution
• Used in iodometric titrations
• Color appears or disappears based on titration type

3. Potassium Dichromate (K₂Cr₂O₇):

• Orange color characteristic
• Self-indicating in certain redox reactions
• Less commonly used than KMnO₄

Application Context: The choice depends on the specific titration type and reaction conditions (acidic, basic, or neutral medium).