Question

Role of \[KMn{O_4}\] in the given titration can be described as
A. Oxidizing agent
B. Reducing agent
C. Indicator
D. Oxidizing agent and indicator

Answer 1

Hint: \[KMn{O_4}\] mainly act as an indicator because the permanganate ions have a deep purple color and during this redox titration, \[Mn{O_4}^-\] is reduced to the colorless manganese ions (\[M{n^{2 + }}\]) in the acidic medium.

Complete step by step answer:
In this question we have been asked, in the titration what is the role of \[KMn{O_4}\]. Let's assume we are titrating \[KMn{O_4}\] with oxalic acid. We'll take \[KMn{O_4}\] in burette and oxalic acid and sulphuric acid in conical flask and we'll start titrating. When a drop of purple color \[KMn{O_4}\] falls in the oxalic acid the purple color of the drops changes to colorless in an acidic medium, and at some point the color of the drop of \[KMn{O_4}\] will not change. In this titration \[KMn{O_4}\] is acting as a self- indicator and lets understand the reaction between \[KMn{O_4}\] and oxalic acid.
As we can see in this reaction, the Oxalic acid is oxidised to carbon dioxide by \[KMn{O_4}\] which itself gets reduced to \[MnS{O_4}\]. Here, \[KMn{O_4}\] is acting as an oxidizing agent and as we know in the presence of sulphuric acid, it acts as a strong oxidizing agent. So, in this titration, \[KMn{O_4}\] is an oxidizing agent and a self- indicator.
So, the correct option will be D i.e Oxidizing agent and indicator.

Note:
In this titration we add sulphuric acid with oxalic acid because sulphuric acid makes the solution acidic and in acidic solution, \[KMn{O_4}\] acts as a strong oxidizing agent.