Question

Why is HCl not used to make the medium acidic in oxidation reactions of KMnO\(_4\) in acidic medium?

• A. KMnO\(_4\) is weaker oxidizing agent than HCl
• B. KMnO\(_4\) oxidises HCl into Cl\(_2\), which is also an oxidizing agent
• C. Both HCl and KMnO\(_4\) act as oxidizing agents
• D. KMnO\(_4\) acts as a reducing agent in the presence of HCl

Hint:

In redox reactions, be cautious about using strong oxidizing agents like KMnO\(_4\) with reducing agents like HCl, as they may produce unwanted products like Cl\(_2\).

Answer 1

The Correct Option is B

When HCl is used in the presence of KMnO\(_4\), KMnO\(_4\) (potassium permanganate) acts as a strong oxidizing agent. KMnO\(_4\) oxidizes chloride ions (Cl\(^-\)) from HCl to chlorine gas (Cl\(_2\)): \[ \text{2 Cl}^- + \text{2 H}^+ → \text{Cl}_2(g) + \text{H}_2\text{O} \] Since Cl\(_2\) is also a strong oxidizing agent, this reaction competes with the oxidation of KMnO\(_4\), preventing HCl from acting as an acidic medium. Thus, HCl is not suitable for making the medium acidic in oxidation reactions of KMnO\(_4\).
Final Answer: \[ \boxed{\text{The correct answer is (2), KMnO}_4\text{ oxidizes HCl into Cl}_2\text{, which is also an oxidizing agent.}} \]