Hygroscopic

Hygroscopic refers to the ability of a substance to attract and hold water molecules from the surrounding environment through either absorption or adsorption. This property is achieved through physical or chemical means. Hygroscopic substances include cellulose fibers such as cotton and paper, sugar, caramel, honey, glycerol, ethanol, wood, methanol, sulfuric acid, many fertilizer chemicals, many salts and synthetic polymers.

Overview

Hygroscopic substances are used in a variety of industries. They are integral to the functioning of many technological devices, and are also used in food storage to keep products dry. They are also found in many organisms, which use hygroscopic substances to maintain moisture levels.

Hygroscopy and Deliquescence

While hygroscopy refers to the absorption of water, deliquescence refers to the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution. Deliquescence occurs when the vapour pressure of the solution that is formed is less than the partial pressure of water vapour in the air.

Applications

Hygroscopic substances have a wide range of applications. They are used in the baking industry to prevent drying. They are also used in the pharmaceutical industry where they are used to keep substances dry and increase their shelf life. In the chemical industry, hygroscopic substances are used to remove water from chemical reactions that are sensitive to water.

See Also

• Deliquescence
• Desiccant
• Humectant
• Efflorescence

References

Hygroscopic Resources
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