Indicator Endpoints in Permanganatometry

Formula / Core Reaction:

$$\text{MnO}_4^- \text{ (Deep Purple)} + 5e^- + 8\text{H}^+ \rightarrow \text{Mn}^{2+} \text{ (Faint Pink / Colorless)}$$

Concept: $$\text{KMnO}_4$$ acts as its own indicator (self-indicator). The addition of a single drop of excess $$\text{MnO}_4^-$$ beyond the stoichiometric equivalence point turns the colorless solution permanently faint pink.

Notation / Key Observation:

• Self-Indicator: $$\text{KMnO}_4$$;
• Endpoint signal: Colorless to permanent light pink.