Question

Why is HCl not used to make the medium acidic in oxidation reactions of $KMn{{O}_{4}}$ in an acidic medium?
A. Both HCl and $KMn{{O}_{4}}$acts as oxidizing agents
B. $KMn{{O}_{4}}$ oxidizes HCl into $C{{l}_{2}}$ which is also an oxidizing agent
C. $KMn{{O}_{4}}$ is a weaker oxidizing agent than HCl
D. $KMn{{O}_{4}}$ acts as a reducing agent in the presence of HCl

Answer 1

Hint: Chlorine gas acts as an oxidizing agent and gets reduced. This is due to the fact that it has the ability to gain electrons. Potassium permanganate $KMn{{O}_{4}}$is also known as a good oxidizing agent. HCl is a strong acid.

Complete answer:
Oxidation reactions occur where the substance takes up electrons and gains oxygen atoms or removes hydrogen atoms. These reactions may happen in acidic or alkaline mediums. For acidic medium in the oxidation of potassium permanganate $KMn{{O}_{4}}$, hydrochloric acid is not used to provide the acidic environment for the reaction.
The reaction when HCl is used alongside potassium permanganate$KMn{{O}_{4}}$ is as follows:
$KMn{{O}_{4}}+16HCl\to 2KCl+2MnC{{l}_{2}}+8{{H}_{2}}O+5C{{l}_{2}}$
Since, the reaction shows the formation of chlorine gas, which is itself a good oxidizing agent, therefore hydrochloric acid is not able to provide the acidic medium as potassium permanganate $KMn{{O}_{4}}$ oxidizes the HCl into chlorine gas.
Hence, HCl gas is not used as $KMn{{O}_{4}}$ oxidizes HCl into $C{{l}_{2}}$ which is also an oxidizing agent.

So, option B is correct.

Note:
For making the medium acidic in the oxidation reactions of potassium permanganate $KMn{{O}_{4}}$, the acid sulphuric acid, ${{H}_{2}}S{{O}_{4}}$ is used. This ${{H}_{2}}S{{O}_{4}}$ does not get oxidized by the $KMn{{O}_{4}}$ and provides a perfect acidic medium. This is practically applied in doing the titrations.