Question

In what way, hygroscopic substances differ from deliquescent substances.

Answer 1

The difference between hygroscopic and deliquescent substances is in the extent to which each material can absorb moisture. This is because both of these terms are very much related to each other and they refer to the property of observing and the retention of moisture from the air. However, they differ in the extent of absorption of moisture where hygroscopic materials absorb moisture but not to the extent the original substance dissolves in it, which is the case with deliquescence. Therefore deliquescence can be regarded as an extreme condition of hygroscopic activity.

Difference between hygroscopic substances and deliquescence,

Hygroscopic Substances	Deliquescence Substances
When exposed to the atmosphere at ordinary temperature, they absorb moisture and do not dissolve.	When exposed to the atmospheric air at ordinary temperature, they absorb moisture and dissolve.
Hygroscopic substances do not change their physical state on exposure to air.	Deliquescent substances change their physical state on exposure to air.
Hygroscopic substances may be amorphous solids or liquids.	Deliquescent substances are crystalline solids.