Question

How $KMnO_{ 4 }$ [Potassium Permanganate] is prepared from $MnO_{ 2 }$? Write equations.

Answer 1

Hint: To prepare the potassium permanganate ($KMnO_{ 4 }$) you need an alkali metal hydroxide and an oxidizing agent along with pyrolusite ($MnO_{ 2 }$). Now try to answer this question accordingly.

Complete step by step answer:

Let’s discuss the stepwise answer to this question -

Potassium Permanganate ($KMnO_{ 4 }$) is an inorganic chemical compound. It is also known as Condy’s crystals or permanganate of potash.
As we already know Potassium permanganate ($KMnO_{ 4 }$) is produced industrially from manganese dioxide ($MnO_{ 2 }$), which also occurs as the mineral pyrolusite. The $MnO_{ 2 }$ is fused with potassium hydroxide and heated in air or with another source of oxygen, like potassium nitrate or potassium chlorate. This process gives potassium manganate:
$2MnO_{ 2 }\quad +\quad 4KOH\quad +\quad O_{ 2 }\quad \rightarrow \quad 2K_{ 2 }MnO_{ 4 }\quad +\quad 2H_{ 2 }O$
The potassium manganate is then converted into permanganate by electrolytic oxidation in alkaline media:
$2K_{ 2 }MnO_{ 4 }\quad +\quad 2H_{ 2 }O\quad \rightarrow \quad 2KMnO_{ 4 }\quad +\quad 2KOH\quad +\quad H_{ 2 }$

Therefore, we prepared $KMnO_{ 4 }$ [Potassium Permanganate] from $MnO_{ 2 }$.

Additional information:
Potassium permanganate is a very strong oxidizing agent and can, therefore, be used as an oxidant in a wide spectrum of chemical reactions.
The oxidizing power of potassium permanganate can be seen while performing a redox reaction with it, in which the dark purple solution turns colorless and then into a brown solution.

Note: We should also know that Potassium manganate can be oxidized by chlorine or by disproportionation under acid conditions.
The chlorine oxidation reaction is
$2K_{ 2 }MnO_{ 4 }\quad +\quad Cl_{ 2 }\quad \rightarrow \quad 2KMnO_{ 4 }\quad +\quad 2KCl$