when we are using potassium dichromate (K2CR2O3) we are using BDS indicator but in case of potassium permanganate we dont use indicator why?..........

Hello there,

Because potassium permanganate has a deep violet colour which is highly visible to the naked eye and when one titrates it and there is a loss of colour, it is apparent. So one does not need an indicator to tell you the end point.

Potassium permanganate acts as self indicator in the presence of acidic medium

Potassium Permanganate is an oxidizing agent, which is of deep violet colour. When used in redox titration, it get reduced into brown coloured Mn2+ ion(In acidic media) at end point and colour change at end point can be detected easily. Since detecting end point is the role of indicator, later is not required in Permanganate titration.

Thank you all

As Mr.Anumolu rightly said Potassium permanganate acts as self indicator and it changes colour (purple --> colourless) when the end point is reached, so there isnt a need to add any indicator.

sensitivity of eye to detection of purple color is high relative to yellow color,phsically.

Color change of Pot per mangnate to Mn2+ is clearly visible being in visible range hence no indicator is required

Z. Aly answer is correct completely. The intensity of permanganate color is  comparable with color intesity if  indicators, and  the end-product (Mn(2+) is colorless (very pale pink) in dilute aq. solutions, the color change can be seen very well. 

In titrations involving potassium permanganate (KMnO4), an external indicator is typically not used because potassium permanganate itself acts as a self-indicator. The reasons for this are based on the chemical properties and the behavior of potassium permanganate in titration reactions:

1. **Strong Oxidizing Agent**: Potassium permanganate is a potent oxidizing agent. In acidic solutions, it gets reduced to manganese(II) ions (Mn2+), which are colorless.

2. **Color Change**: KMnO4 is a deep purple or magenta color in solution. Upon reduction, it loses its color, changing to a very faint pink or colorless state. This color change is sharp and distinct, making it easy to detect the endpoint of the titration.

3. **Self-Indicating Property**: The transition from the deep purple of unreduced KMnO4 to the faint pink or colorless Mn2+ ions serves as its own indicator. When all the analyte is consumed in the reaction, the next small excess amount of KMnO4 added imparts a light pink color to the solution, indicating the endpoint.

4. **Sensitivity**: The endpoint, marked by the appearance of a pale pink color that persists for about 30 seconds, is usually very sharp. This makes potassium permanganate an effective titrant for redox titrations without the need for an additional indicator.

5. **Types of Reactions**: KMnO4 is commonly used in redox titrations involving organic compounds, oxalates, ferrous ions, and other reducing agents. The self-indicating nature of KMnO4 is particularly advantageous in these reactions.

6. **Practical Considerations**: Using KMnO4 as a self-indicator simplifies the procedure and avoids potential interferences or errors that might arise from using an additional chemical as an indicator.

In summary, the use of potassium permanganate as both the titrant and the indicator in titrations is due to its strong oxidizing nature and the distinct color change it undergoes upon reduction. This makes it a convenient and reliable choice for various redox titrations.

l Perhaps this protocol list can give us more information to help solve the problem.