Potassium Permanganate : The all rounder salt

If you've seen a well being cleaned, you may have noticed that a reddish brown powder is thrown into it. That would be potassium permanganate, which is one of chemistry's most useful substances.


The germ fighter


Potassium permanganate is a strong oxidising agent when dissolved in water.

KMnO4 + H2O → MnO2 + K+ + OH- + O*

The oxygen free radical is a powerful toxin, and kills off bacteria and fungi. That's why potassium permanganate is used to clean not just wells, but also fish tanks, water storage tanks, water pipes etc.

You can use a dilute solution of KMnO4 (which is pinkish red in colour) to treat mild skin infections, bruises, sores etc. But don't ever use it on cuts or deeper wounds. If you keep an aquarium, you can use a very mild solution to keep your fishes free from bacteria.

It is used in laboratories, poultry farms and hospital wards as a fumigation agent to kill fungi. During fumigation, the cleaner puts one gram of potassium permanganate in an earthen dish, and then pours 2 ml of formaldehyde over it. He then runs away as fast as he can and shuts the door of the room. As a violent reaction happens, formaldehyde gas spreads across the room, killing everything.

Dip anything in potassium permanganate solution, and it will look as if it was a hundred years old. This trick is used in movies like Indiana Jones, where the hero goes looking for ancient treasures. Try this out at home, but carefully!


The superchemical


Potassium permanganate is an important reagent used to manufacture many important organic chemicals. These include ascorbic acid (Vitamin C), chloramphenicol (an antibiotic) and saccharine (sweetening agent).

Sometimes, soldiers are given small amounts of potassium permanganate and glycerine. When they are in a place where they need a quick fire, they mix the two, and they've got a fire going. This fire can be very explosive, so don't try this at home or in the lab. A mix of KMnO4 and hydrogen peroxide is used as a propellant for torpedoes.

The manganese oxide (MnO2) left behind by potassium permanganate reactions is deep brown in colour and leaves permanent stains. If your clothes have been stained, you can apply some vinegar over the stain and leave it for two days. The acetic acid in the vinegar will dissolve the oxide, and the colour will fade.

Comments

Popular posts from this blog

Why do onions make you cry?

The sparkling truth about Diamonds