What Is Sodium Chloride?
Sodium chloride, the main component of seawater, naturally occurs as rock salt.
Commonly known as salt or dietary salt, sodium chloride was initially used for food or medical purposes. Today, it is mass-produced in factories through seawater refinement using ion exchange membranes, among other processes. In laboratories, sodium chloride can be synthesized by neutralizing hydrochloric acid with sodium hydroxide.
Sodium chloride plays a crucial role in maintaining osmotic pressure in the blood and tissues of animals.
Uses of Sodium Chloride
Sodium chloride serves as a raw material for various sodium compounds and is the primary ingredient in salt, widely used in seasonings. Its antiseptic and sterilizing properties make it essential for preparing salted and preserved foods.
In cosmetics, sodium chloride is used to adjust thickness, stabilize emulsions and suspensions, and as an electrolyte supplement due to its significant physiological roles. It also acts as a solubilizer, buffer, boiler water softener, and anti-freeze agent, lowering the water’s freezing point.
Properties of Sodium Chloride
Sodium chloride dissolves well in water but not in ethanol. It forms an ionic crystal of sodium and chloride ions. In its crystalline form, it is an insulator, but its aqueous solutions conduct electricity.
Odorless and with a distinctive salty taste, pure sodium chloride remains non-deliquescent up to 75% humidity at 20°C (68°F).
It has a density of 2.16 g/cm3, a melting point of 800.4°C, and a boiling point of 1,413°C. Sodium chloride conducts electricity when melted, separating into chloride and sodium ions.
Sodium chloride, NaCl, has a formula weight of 58.44. It is a colorless crystalline solid with a face-centered cubic lattice and octahedral coordination.
Other Information About Sodium Chloride
1. Crystallization of Sodium Chloride
Sodium chloride’s solubility changes little with temperature, yielding only a small amount of crystals upon cooling. Evaporation or the introduction of hydrogen chloride gas is used to concentrate sodium chloride solutions for crystallization.
2. Sodium Chloride as a Resource
Seawater and rock salt are abundant sources of sodium chloride, contributing to the annual global production of 280 million tons. Japan, one of the largest salt importers, imports around 7 million tons yearly, with a self-sufficiency rate of about 11%, relying heavily on imports for industrial salt despite its island geography.
3. Applications of Sodium Chloride
Sodium chloride’s versatility extends to fire extinguishing agents for metallic sodium, magnesium, and potassium fires, enhancing fluidity and moisture resistance when mixed with low melting point cross-linking agents. It is colored light blackish brown for identification.
It is also used in infrared optics as prisms, lenses, and windows, and in rubber manufacturing for neoprene, buna, and white rubber. Additionally, saltwater and sulfuric acid coagulate emulsified latex in rubber production.
Due to its hygroscopic nature, sodium chloride serves as an inexpensive desiccant and regenerates ion exchange resins in water-softening systems. It is a common educational tool in schools for studying solubility changes.