Compounds of metals and halogens can feature ionic or covalent bonding. An example of a salt containing an ionic bond between a metal and a halogen is potassium chloride. It is a salt made up of potassium (K) and chlorine (Cl). Its chemical formula is KCl. Some important properties and uses of potassium chloride are discussed in this article.
Physical Properties
The molar mass of KCl is 74.55 grams per mole. It has a white, crystalline appearance and is solid at room temperatures. It is an odorless salt with a density of 1.984 grams per cubic centimeter. The melting point of potassium chloride is 770oC (or 1040 K) and its boiling point is 1420oC. This salt is quite soluble in water, having a solubility of 253.9 grams per liter at a temperature of 20oC. At 100oC, its solubility in water increases to 360.5 grams per liter. It is also soluble in glycerol and alkalis. The structure of the crystals of potassium chloride is similar to that of sodium chloride. The crystals have an FCC (face-centered cubic) structure.
Chemical Properties
When subjected to a flame test, powdered potassium chloride burns with a lilac flame. Even though potassium is more electropositive than sodium, the heating of potassium chloride with metallic sodium to 850oC yields potassium in its metallic form. The chemical equation for this reaction is given by:
KCl + Na ⇌ NaCl + K
Potassium chloride is a salt that can be obtained from hydrochloric acid (HCl) and potassium hydroxide (KOH). This method of producing KCl features a neutralization reaction between a strong acid and a strong base. Aqueous solutions of potassium chloride are neutral in nature.
Uses of Potassium Chloride
Potassium chloride is used in the production of a fertilizer called potash. The limited availability of potassium is one of the primary inhibitors of plant growth. The two major forms of this fertilizer are the sulfate of potash (also known as potassium sulfate) and the Muriate of potash (potassium chloride).
The oral consumption of potassium chloride is often recommended to treat cases of hypokalemia (low blood potassium). It can also be administered intravenously via IV drips.
KCl is also used as a salt substitute in the preparation of food. However, this compound has a weak and unsalty flavor and is often found to be bitter. Therefore, it is mixed with sodium chloride to form low-sodium salts.
This compound is also very important in the industrial manufacture of potassium metal and potassium hydroxide. It is also used as a supplement in animal foods in order to increase the nutritional value. To learn more about this ionic salt and the important uses of acids and bases, subscribe to the BYJU’S YouTube channel and enable notifications.