Preparation of potassium permanganate from MnO2 involves two-step process in which the 1^ st step is a reaction with KOH

Question

Preparation of potassium permanganate from MnO2 involves two-step process in which the 1^ st step is a reaction with KOH and KNO3 to produce:

Accepted Answer

Given: Preparation of potassium permanganate from $\mathrm{MnO_2}$ occurs in two steps, and the first step uses $\mathrm{KOH}$ and $\mathrm{KNO_3}$ .

Find: The product formed in the first step.

In the first step, manganese dioxide reacts with potassium hydroxide and an oxidizing agent to form potassium manganate.

\mathrm{MnO_2 + 2KOH + \frac{1}{2}O_2 \rightarrow K_2MnO_4 + H_2O}

The solution also states this intermediate is potassium manganate, which is then converted further into potassium permanganate in the next step.

\mathrm{3K_2MnO_4 + 2CO_2 \rightarrow 2KMnO_4 + 2K_2CO_3 + MnO_2}

Therefore, the product formed in the first step is $\mathrm{K_2MnO_4}$ . The correct option is D.

Given: Potassium permanganate is prepared from $\mathrm{MnO_2}$ in two steps.

Find: Which compound is produced in the first step when $\mathrm{MnO_2}$ reacts with $\mathrm{KOH}$ and $\mathrm{KNO_3}$ .

Step 1 gives potassium manganate as the intermediate compound.

\mathrm{MnO_2 + 4KOH + 2KNO_3 \rightarrow K_2MnO_4 + 2H_2O}

So the first-step product is potassium manganate, not potassium permanganate.

Therefore, the correct answer is $\mathrm{K_2MnO_4}$ , corresponding to option D.

Answer