Question

Preparation of potassium permanganate from MnO\(_2\) involves a two-step process in which the 1^st step is a reaction with KOH and KNO\(_3\) to produce:

• A. \( K_4[{Mn(OH)}_6] \)
• B. \( K_3{MnO}_4 \)
• C. \( {KMnO}_4 \)
• D. \( K_2{MnO}_4 \)

Hint:

In the first step of preparing potassium permanganate, potassium manganate (\( {K}_2{MnO}_4 \)) is formed by reacting manganese dioxide with potassium hydroxide and potassium nitrate. This is then further oxidized to potassium permanganate.

Answer 1

The Correct Option is D

Preparation of Potassium Permanganate (\( \text{KMnO}_4 \)) from Manganese Dioxide (\( \text{MnO}_2 \)) 

Given: The preparation of potassium permanganate involves two steps. In the first step, manganese dioxide (\( \text{MnO}_2 \)) reacts with potassium hydroxide (KOH) and potassium nitrate (\( \text{KNO}_3 \)) to form potassium manganate (\( \text{K}_2\text{MnO}_4 \)).

Step 1: The reaction

The reaction is as follows: \[ \text{MnO}_2 + 4 \text{KOH} + 2 \text{KNO}_3 \to \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \] - Manganese dioxide reacts with potassium hydroxide and potassium nitrate to produce potassium manganate and water.

Conclusion:

The product of the first step is \( \boxed{\text{K}_2\text{MnO}_4} \), which corresponds to option (4).