Properties of Sodium Chloride (Common Salt)

Historic Importance of Common Salt
Salt is being used as a preservative since ancient times. Salt was first found on the Chinese land way back in 6000 BC. The traders from Egypt had begun exporting salt to the Phoenicians, since 2800 BC. Egyptians used salt in their funeral offerings. Some sources have revealed an interesting fact that in ancient times, the soldiers were paid in salt. It was this precious substance for which Mahatma Gandhi led the Dandi march. The result of the march was that, the British rulers had to cancel the acts passed which led to an increase in unity among the people.

Overview: Salt Properties
Now, let us discuss the properties of sodium chloride. Molar mass of sodium chloride is 58.443 grams/mole. It is white in color and is a crystalline solid. Sodium chloride does not have any odor. Its solubility in water is different at different temperatures. Let us consider the solubility of sodium chloride in 100 milliliters of water. At 0 degree Celsius, its solubility is 35.6 grams, at 25 degree Celsius, it is 35.9 grams and at 39.1 degree Celsius, it is 39.1 grams. The melting point of sodium chloride is 801 degree Celsius or 1074 degree Kelvin, while its boiling point is 1465 degree Celsius or 1738 degree Kelvin.

Sodium chloride is soluble in glycerol, ethylene glycol and formic acid. It is insoluble in hydrochloric acid (HCL). The solubility in methanol is 1.49 grams in 100 milliliters of methanol. The solubility in ammonia is 2.15 grams per 100 milliliters of ammonia. The refractive index of NaCl is 1.5442. Its density is 2.165 grams per cubic centimeters. The molecular weight is 58.45. The Young's modulus for sodium chloride is 39.96. The most important property of sodium chloride is that, it is inflammable. It has a face centered cubical structure. Sodium and chlorine can be separated by the process of electrolysis in which electric currents are passed through the mixture. Sodium chloride has a strong taste. Properties of salt have a significant importance in the study of chemistry. Salt properties remain constant irrespective of the prevailing conditions.

Sources of Common Salt
Sodium chloride is available on a large scale. It is nature's gift to mankind. It is present in a mineral called as Halite. Halite is also known as rock salt. Salt content in the Dead Sea is as high as 34%. Sodium chloride is found in salt lakes in the form of of a mixed evaporate. Sometimes, it is recovered from mines. It is produced in large quantities by mining rock salt. It is also produced by evaporation of sea water from salt lakes and brine wells.

Different Forms of Salt
Unrefined salts, refined salts and table salts are the various existing forms of salt. Bathing additives and cosmetics are produced from unrefined salts. Refined salt is prepared by recrystallization of raw salt. Sodium ferrocyanide is added as an anticaking agent to the brine solution, as it is a hygroscopic chemical capable of absorbing humidity. This prevents the salt crystals from sticking to each other. Table salt contains 60 to 99 percent sodium chloride. The true density of table salt is 2.165 grams per cubic centimeters, while its bulk density is 1.154 grams per cubic centimeters.

Uses of Sodium Chloride
There are many uses of sodium chloride. Cooking is the primary use of salt. It is also used to make soaps and detergents. Paper is manufactured from salt. Textile industries use salt for setting dyes. Chlorine is prepared from sodium chloride. This chlorine is further used to prepare pesticides. Calcium chloride and sodium carbonate can be prepared from sodium chloride. Salt is used as a cleansing agent and also in shampoos. Salt contains iodine, which is essential for the synthesis of thyroid hormones. Salt modulates the water content of the human body. Sea salt helps in formation of clouds. Bathing additives and cosmetic products are prepared from sea salts. Epsom salts provide relaxation to the body, act as pain killers and prevent blood clotting.

Disadvantages of Common Salt
Salt causes irritation of eyes and skin. Over consumption of salt can cause high blood pressure. Heartburn or pyrosis, which means burning sensation or chest pain, is also the ill effect of over consumption of salt. Intake of salt in large quantities and in a short period of time, can cause death. Hypertension, gastric cancer and osteoporosis are other health disorders caused by common salt.

Thus, common salt is of great importance to human beings. The sulphates, carbonates and hydroxides of sodium are also useful in our day to day activities only because of the utilitarian properties of sodium chloride (common salt).