Question

In the titration of potassium permanganate (KMnO\(_4\)) against Ferrous ammonium sulphate (FAS) solution, dilute sulphuric acid but not nitric acid is used to maintain acidic medium, because

• A. Nitric acid doesn’t act as an indicator
• B. Nitric acid itself is an oxidising agent
• C. Nitric acid is a weak acid than sulphuric acid
• D. It is difficult to identify the end point

Hint:

In redox titrations, it's crucial to avoid using strong oxidizing acids like nitric acid because they can interfere with the reaction you're trying to measure. Sulfuric acid is the preferred choice in this case.

Answer 1

The Correct Option is B

In the titration of ferrous ammonium sulfate with potassium permanganate, an acidic medium is necessary to maintain the iron(II) ions in solution. The reason dilute sulphuric acid is preferred over nitric acid is because nitric acid is itself an oxidizing agent, and it would interfere with the redox reaction. - Sulfuric acid does not have strong oxidizing properties and does not interfere with the redox reactions between KMnO\(_4\) and FAS. - On the other hand, nitric acid would oxidize the iron(II) ions to iron(III), which would skew the titration results. Thus, the correct answer is: \[ \text{(2) Nitric acid itself is an oxidising agent} \]