Question 17Differentiate between an efflorescent, deliquescent & hygroscopic substance with suitable examples.

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PropertyEfflorescent SubstanceDeliquescent SubstanceHygroscopic SubstanceNatureCrystalline - hydratedCrystalline - water solubleAmorphous - solids or liquidsOn exposure to atmosphereLose moisture - partly or completely to the atmosphereAbsorb moisture- from the atmosphere.Absorb moisture- from the atmosphere.Change in stateChanges into an amorphous powderChanges into a saturated solutionDo not change their original state.ExampleNa2CO3.10H2O washing soda⟶Na2CO3.H2O\underset{	ext{ washing soda} }{	ext{Na}_2	ext{CO}_3.10	ext{H}_2	ext{O}} \longrightarrow {	ext{Na}_2	ext{CO}_3.	ext{H}_2	ext{O}} washing sodaNa2​CO3​.10H2​O​⟶Na2​CO3​.H2​OFeCl3 crystals⟶FeCl3 solution\underset{	ext{ crystals} }{	ext{FeCl}_3} \longrightarrow \underset{	ext{ solution} }{	ext{FeCl}_3} crystalsFeCl3​​⟶ solutionFeCl3​​CaO solid⟶CaO solid\underset{	ext{ solid} }{	ext{CaO}} \longrightarrow \underset{	ext{ solid} }{	ext{CaO}} solidCaO​⟶ solidCaO​

Property	Efflorescent Substance	Deliquescent Substance	Hygroscopic Substance
Nature	Crystalline - hydrated	Crystalline - water soluble	Amorphous - solids or liquids
On exposure to atmosphere	Lose moisture - partly or completely to the atmosphere	Absorb moisture- from the atmosphere.	Absorb moisture- from the atmosphere.
Change in state	Changes into an amorphous powder	Changes into a saturated solution	Do not change their original state.
Example	$\underset{\text{ washing soda} }{\text{Na}_2\text{CO}_3.10\text{H}_2\text{O}} \longrightarrow {\text{Na}_2\text{CO}_3.\text{H}_2\text{O}}$	$\underset{\text{ crystals} }{\text{FeCl}_3} \longrightarrow \underset{\text{ solution} }{\text{FeCl}_3}$	$\underset{\text{ solid} }{\text{CaO}} \longrightarrow \underset{\text{ solid} }{\text{CaO}}$

Water — Question 3

Question 17