Q25 of 50 Page 1

Describe the preparation of potassium permanganate from pyrolusite ore. Write balanced chemical equation for one reaction to show the oxidizing nature of potassium permanganate.

Potassium Permanganate can be prepared from the pyrolusite ore. The pyrolusite is finely powdered and fused with potassium hydroxide or potassium carbonate in the presence of air or an oxidizing agent such as potassium nitrate or potassium chlorate, then a green mass of Potassium Manganate is obtained.

The reaction is follows:


2MnO2 + 4KOH + O2→ 2K2MnO4 + 2H2O


Green Mass


3K2MnO4+ 2CO2 → 2KMnO4 + MnO2 + 2K2CO3


Potassium Permanganate acts as a strong oxidizing agent. The example is as follows:


2KMnO4 + H2O → 2KOH + 2MnO2 + 3O


Due to the tendency of MnO4- ion to get reduced, potassium permanganate acts as an oxidizing agent in the neutral medium.


More from this chapter

All 50 →
25

Is the variability in oxidation number of transition elements different from that of non – transition elements? Illustrate with examples.

 25

Give reasons:

(a) d- block elements exhibit more oxidation states than f-block elements.


(b) Orange solution of potassium dichromate turns yellow on adding sodium hydroxide to it.


(c) Zirconium (Z= 40) and Hafnium (Z = 72) have almost similar atomic radii.

 25

Draw the structures of chromate and dichromate ions.

 26

A ketone A which undergoes haloform reaction gives compound B on reduction. B on heating with sulphuric acid gives compound C, which forms mono-ozonide D. The compound D on hydrolysis in presence of zinc dust gives only acetaldehyde. Write the structures and IUPAC names of A, B and C. Write down the reactions involved.