Question

How can we classify an indicator

Answer 1

› Indicator and Types of Indicator

Indicator and Types of Indicator

The chemical substances which are used to indicate the end point during titration are called indicators.

Types of indicator:

Self indicator: A substance is said to be self indicator if it itself acts as a indicator in titration. Example: KMnO4 acts as a self indicator during the titration of Potassium permanganate (KMnO­­4) and oxalic acid (COOH)2.

Internal indicator: The indicator which is used within the solution is called internal indicator. Example: Methyl orange and phenolphthalein can acts as indicator in acid base titration.

External indicator: The indicator which are not added to the solution are called external indicator. Potassium Ferro cyanide K3[Fe(CN)6] can acts as external indicator during titration of ammonium or ferrous sulphate (FeSO4) with Potassium dichromate (K2Cr2O7)