[Chemistry Class Notes] on Potassium Chloride Pdf for Exam

Potassium chloride is a salt formed from the bonding between an alkali metal and a halide. It consists of a Potassium atom bonding with a Chloride atom. The Potassium chloride chemical formula is KCl. It is formed when the one excess electron in the valence shell of the Potassium atom is transferred to the valence shell of the Chlorine atom so that both the atoms complete their octet valency.   

Structure of Potassium Chloride

Potassium chloride is formed due to the formation of the ionic bonds between the potassium and chlorine atom. Since the electron is transferred between the two atoms, the bond formation is ionic in nature. The atoms are closely packed, where the larger chloride ions are distributed in an array with gaps, also known as octahedral voids, between them. The smaller potassium ions fill in these gaps. Such chemical structure is also observed in the crystal structure of other halide salts.

Properties of potassium chloride

The identity of any chemical compound is defined by its physical and chemical properties. The physical and chemical properties of Potassium chloride are as follows:

• Physical properties

• It is an odorless, crystalline, white solid with a sour taste.

• Face-centered cubic unit cells form the crystal structure of Potassium chloride.

• The melting point of Potassium chloride is 770ᴼC. 

• The boiling point of Potassium chloride is 1420ᴼC.

• The density of Potassium chloride is 1.984 g/mL.

• The molar mass of Potassium chloride is 74.5513 g/ mol.

• Potassium chloride is soluble in water, alcohol, but not in ether. It is also not soluble in organic compounds with the general formula of R-O-R’.

• The solubility of Potassium chloride in water increases with temperature. It is due to the increased Brownian motion caused between the atoms in increased temperature. The solubility of Potassium chloride is 217.1 g/L at 0ᴼC, 253.9 g/L at 20ᴼC, and 360.5 g/L at 100ᴼC.

• The pH of Potassium chloride is about 7.

• Chemical Properties

• Potassium chloride can be completely ionized into potassium and chloride ion in water. Therefore, an aqueous solution of Potassium chloride gas very high electrical conductivity.

• Potassium chloride can be reduced to potassium by reacting with sodium, although the position of sodium in the electropositivity series is lower than that of potassium. The dissociation reaction of Potassium chloride into potassium by sodium takes place at 850ᴼC.

• kcl in Chemistry – KCl+Na⇌ NaCl + K – 

• Potassium Chloride burns with lilac or a pale violet-colored flame, and this is the characteristic for most potassium-containing compounds.

• KCl is widely used in chemistry as an essential component of most chemical reactions.

Uses of potassium chloride

The application of potassium chloride has extended into industrial and medical arenas. Some of the uses of potassium chloride are as under:

• It is used widely as a component for agricultural fertilizer. It is used to make Potash, which is an important source of potassium for plant growth.

• It is used to treat cases of extremely low blood pressure.

• It is used in cooking as a substituent for sodium chloride since it is required in a lesser amount.

• It is used for cooking food for high blood pressure patients.

• It is used in the industry as the raw material to manufacture potassium metal.

• It is used in the soap industry as a water softening agent as an alternative to sodium chloride.

• Potassium chloride can be used in the calibration of radiation monitoring equipments as a source for beta radiation.

• Potassium chloride is used for the flux in oxy-fuel welding machines for the welding of aluminum. This is one of the important KCL uses.