Question

What is the formula, molar mass, and colour of Potassium Permanganate ?

Answer 1

Hint: To solve the given problem, we should have the knowledge about Potassium Permanganate, and how to calculate the molar mass of a compound.
Potassium Permanganate is an inorganic compound made from pyrolusite ore. Pyrolusite ore is $ MnO_2 $ which is brown in colour. It is reacted with Potassium hydroxide to form Potassium permanganate. Potassium Permanganate is an oxidising agent in all mediums .
Molar mass of a compound is calculated by adding the standard atomic mass and multiplying it with their number of atoms.

Complete step by step solution:
Step-1 :
Potassium permanganate is prepared by the disproportionation of potassium manganate in acidic medium.Potassium permanganate is purple in colour and has a formula of $ KMnO_4 $. The potassium manganate formed is green in colour.
Step-2 :
The molecular formula of Potassium permanganate is $ KMnO_4 $ . The molar mass of $ KMnO_4 $ can be calculated as ( Atomic mass of $ K $ ) $ + $ (Atomic mass of $ Mn $) $ + $ $ 4 \times $ (Atomic mass of $ O $).
$ = 158 g mol^ { -1 }$.

Note:
The preparation and colour and formula for some selective compounds should be remembered. The molar mass can be achieved later.
Chemical formula for Potassium manganate is $ K_2MnO_4 $ and molar mass is $ 197 g mol^ { -1 }$. Because of the action of heat, Potassium manganate gets converted to potassium permanganate along with $ MnO_2 $ and $ O_2 $.