Potassium – Properties and Applications

Chemical Formula

K

Topics Covered

Background
Basic Information
Occurrence
Isotopes
Production of Potassium Element
Health Aspects
Key Properties
Applications

Background

In 1807AD, potassium was first prepared by English chemist Sir Humphrey Davy. Davy melted a small amount of potash, and an passed electric current through it. He discovered that a small liquid droplet of metal had formed. This droplet was the man-made sample of potassium to be prepared. first portion of potassium to be seen by man. Davy named the element after its much older term "potash". Potash is also known as vegetable alkali.

In 1808 French chemists Louis-Josef Gay-Lussac and Louis-Jacques Thenard, were also able to prepare potassium by heating a mixture of potassium hydroxide and iron fillings at high temperature.

Basic Information

Table 1 . Basic Properties of Potassium

Occurrence

Potassium is the 7 8 th most abundant element found the crust of the Earth. Potassium also occurs in different minerals e.g. sylvite, carnallite, langbeinite, and polyhalite.

Isotopes

There is some debate as to how many isotopes of potassium exist, with numbers ranging from 17 to 25. The three naturally occurring isotopes are Potassium-39, Potassium-40 and Potassium-41.

Potassium 40 is of special interest to scientists as it has been proved that nearly everything on earth contains at least a tiny amount of radioactive potassium-40. It is used to measure the age of rocks. In older case the rock s tyheer will be a greater proportion of is old there will be more of argon-40 and less er proportion of potassium-40 , compared to younger rocks where the converse is true and if the rock is younger, it will be vice-versa.

Production of Potassium Element

Potassium compounds can be extracted from the earth as it is found in many solids, soil and seawater. The earliest version known to man was potash, which could be easily obtained by simply burning a tree and gathering potash from the ashes. Potash was also produced from large salt mine blocks that were formed when ancient seas dried up. Significant potassium rich mineral deposits are known to exist in Germany, USA, Canada and Russia.

Commercially, potassium can be produced using two processes – thermochemical distillation and electrolytic process es.

Health Aspects

One of the three primary nutrients required by plants for growth and good health is potassium.

Potassium has many important roles in the human body as well.

• It helps control the balance of fluids in cells and body fluids in a better manner.
• It enables contraction of muscles and transmission of chemical messages between nerve cells.
• It aids digestion of food and the proper functioning of the eye.
• In most of these, potassium and sodium work together to enable these functions to work properly

Key Properties

Key properties of potassium include:

• Is a soft, silvery-white waxy metal that can be easily cut with a knife
• Density is less than that of water
• Can be melted over a candle flame, as it has very low melting point than many other metals
• It is V very reactive and nefer found in nature in the elemental form
• Reacts with all acids, and all non-metals e.g. nitrogen, fluorine sulfur, chlorine, and phosphorus
• Reacts violently with water
• Must be stored in a non-aqueous - non-oxygen environment s such as naphtha or kerosene as it spontaneously catche s fire upon exposure to water and readily oxidizes when exposed to oxygen
• Flame test produces a lilac color

Applications

Due to its high degree of reactivity, potassium is rarely used in its elemental /metallic form. Some a pplications of potassium compounds include:

• It is used as a powerful reducing agent in organic chemistry.
• Potassium/Sodium alloys are It used as a heat exchange medium . The heat in the potassium warms water and makes it hot enough to boil. Then water is c hang ed into steam, which is used to work devices that generate electricity. To generate electricity and in n uclear reactors.
• It is used to manufacture potassium superoxide (KO 2), which is used to regenerate oxygen (and absorb carbon dioxide) in the air in submarines, mines and space vehicles.

Source: AZoM.com