To understand the preparation of potassium permanganate ( ) from manganese dioxide ( ), we need to look at the multi-step reaction process involved. This involves the following steps:
- The first step in the process involves heating manganese dioxide ( ) with potassium hydroxide ( ) and an oxidizing agent like potassium nitrate ( ) or oxygen. The general reaction is:
As per the question, the product of this first step is potassium manganate ( ). This is an intermediate in the preparation of potassium permanganate.
- In the subsequent step, the produced potassium manganate ( ) is oxidized further to form potassium permanganate ( ). This is usually done by bubbling carbon dioxide or by further chemical oxidation:
With this understanding, we can conclude that the correct product formed in the first step is potassium manganate ( ).
Let's rule out the incorrect options:
- : This chemical formula does not correspond to any known products in the formation of potassium permanganate.
- : Potassium manganate's formula is , not .
- : This is the final product of the process, not the product of the first step.
Therefore, the correct answer is .