Potassium permanganate

Introduction

KMnO4 is the chemical formula for potassium permanganate, an inorganic molecule. It’s a crystalline purplish-black salt. Potassium permanganate is extensively used as a strong oxidizing agent in the chemical sector and labs, as well as a treatment for dermatitis, wound cleansing, and general disinfection.

A brief outline

The solution created when potassium permanganate crystals are exposed to water is purple. It’s a potent oxidizing agent that doesn’t produce any hazardous by-products. Other minerals, such as manganese oxide, are frequently used to make it.

Important concepts

• KMnO₄ – Potassium Permanganate Preparation

Commercial potassium permanganate is made by combining a solution of potassium hydroxide and granular manganese oxide with oxidizing agents such as potassium chlorate. The mixture is cooked until it has evaporated, then heated in iron pans till it acquires a pasty consistency.

• 6KOH + 3MnO₂ + 6KClO₃ → 3K₂MnO₄ + 6KCl + 3H₂O

The potassium manganate (green) is then heated with a huge amount of water and a current of chlorine, CO₂, and ozonized air is circulated through the liquid until permanganate is created. To prevent the MnO₂ from breaking down the permanganate, it is continually removed.

• 6K₂MnO₄ + 3Cl₂ → 6KMnO₄ (Potassium Permanganate) + 6KCl

The KMnO₄ solution is extracted from any concentrated and crystalline MnO₂ precipitate. The crystals are dried after centrifugation.

Potassium Permanganate – KMnO₄ Physical Properties

1. It’s a crystalline substance that’s odourless and ranges from purple to magenta in colour.
2. Water, acetone, acetic acid, methanol, and pyridine are all soluble in it.
3. In ethanol and organic liquids, it dissolves.

Potassium Permanganate Chemical Properties

1. Because potassium permanganate is a powerful oxidising agent, it can be utilised as an oxidant in a wide range of chemical reactions.
2. When initiating a redox reaction with potassium permanganate, the dark purple solution will turn colourless and eventually into a brown solution, demonstrating its oxidising power.

Significance of potassium permanganate in IIT JEE exam

Organic chemistry, which covers compounds and their structures, accounts for about 8.33 per cent of the overall 120 marks on the JEE test. The NCERT textbook is used to solve the majority of the questions on this topic. There will undoubtedly be a few queries about this organic chemistry topic.

FAQs

Permanganate is an excellent oxidizer. Why?

Elements grow more electronegative as their oxidation states increase. As a result, permanganate is an excellent oxidising agent.

What colour does potassium permanganate have?

The physical state of potassium permanganate is an odourless solid that resembles dark purple or bronze crystals. The solution turns purple when these crystals are dissolved in water.

What makes KMnO4 a self-indicator?

When all of the permanganate ions were being used up in the reaction, the solution sheds its pink colour. Potassium permanganate is a self-indicator because it acts as an indication in addition to being one of the reactants.