Question

Washing soda and iron [III] chloride are separately exposed to the atmosphere. State

1. the observations seen
2. the phenomenon which occurs
3. the reason for the phenomenon occurring in each case.

Would a similar phenomenon occur in case of exposure of common salt. Explain giving reasons.

Answer 1

Observations When Exposed To Atmosphere:

(i) Washing soda:

(a) Loses its moisture (water of crystallization)
(b) Becomes amorphous
(c) Coated with white powder

(ii) Iron (III) Chloride (FeCl₂)

Absorbs moisture from atmsophere dissolves in moisture changes to Liquid state

(iii) In case of washing soda — the phenomenon is Efflorescence.
In case of FeCl₃ it is Deliquescence
No, in case of common salt (NaCl) no such phenomenon can occur as, it is Anhydrous salt and does not contain water of crystallization.
When common salt contains impurities of calcium or magnesium chloride dilquescent it absorbs moisture from the atmosphere and becomes sticky and wet.