Sodium chloride is widely distributed in nature. Oceans are the vast source of sodium chloride. It occurs in seawater at an average concentration of 2.68 wt%. It also occurs in many inland saline waters and in salt deposits in sedimentary rocks, as the mineral halite.
Sodium chloride is probably the most important salt of both sodium and chlorine. Sodium chloride, common table salt, is an essential component of most food preparation, imparting flavor to food and providing the sodium nutritional requirement. Also, it is used for preserving food. Therapeutically, NaCl solution is used to combat dehydration as an electrolyte replenisher, and it is an emetic.
The most important applications of sodium chloride in the chemical industry are in making a number of important industrial chemicals such as hydrochloric acid, sodium hydroxide, sodium carbonate, and metallic sodium. It is the starting material in manufacturing these substances. Other uses are in dyeing and printing fabrics, glazing pottery, in making soap, and for curing hides. Sodium chloride is a component of many freezing mixtures.
