Some salts undergo hygroscopy, deliquescence and efflorescence.
What are Hygroscopic Salts?
Hygroscopic salts /compounds are those that absorb water from the atmosphere but do not form a solution.
Some salts which are hygroscopic include anhydrous copper(II)sulphate(VI), anhydrous cobalt(II)chloride, potassium nitrate(V) common table salt.
The hygroscopic nature of these salts is a result of their affinity for water molecules, allowing them to maintain a higher moisture content even in relatively dry conditions. This property makes hygroscopic salts valuable for various applications, such as controlling humidity levels, preserving substances, and facilitating chemical processes that require controlled moisture environments.
What are Deliquescent Salts?
Deliquescent salts /compounds are those that absorb water from the atmosphere and form a solution.
Some salts which are deliquescent include: Sodium nitrate(V),Calcium chloride, Sodium hydroxide, Iron(II)chloride, Magnesium chloride.
Deliquescent salts have the ability to self-dissolve by absorbing ambient moisture. This characteristic sets them apart from being solely hygroscopic, as they take in moisture without necessarily forming a solution.
What are Efflorescent Salts?
Efflorescent salts/compounds are those that lose their water of crystallization to the atmosphere.
Some salts which show efflorescence include: sodium carbonate decahydrate, Iron(II)sulphate(VI)heptahydrate, sodium sulphate (VI) decahydrate.
Unlike deliquescent salts that absorb moisture from the air and dissolve in it, and hygroscopic salts that attract and retain moisture without forming solutions, efflorescent salts lose moisture and can become powdery or crumbly over time. Efflorescence is often observed as a white or chalky deposit on the surfaces of buildings, minerals, or other materials containing these salts.
