is called \& solid crystals of a substance by precipitating it out from its super saturated solution. During crystallisation, a salt is dissolved in water till the solution becomes saturated. The water in this solution is evaporated to get large crystals of the salt. Crystals are the purest form of a solid substance. Crystallisation is commonly used in industries to form the crystals alum from their respective solution. Extraction of Common Salt from Sea Nater Goa water tastes salty because it has salt dissolved in it. Salt is of

Question:
What is Crystallisation? Explain the extraction of common salt from sea water.

Solution:

Crystallisation:
Crystallisation is the process of obtaining pure solid crystals of a substance
by precipitating it out from its supersaturated solution.

During crystallisation:

Step 1:
A salt is dissolved in water until the solution becomes saturated.

Step 2:
The water from the saturated solution is slowly evaporated.

Step 3:
After evaporation, large crystals of the salt are formed.

Important Point:
Crystals are the purest form of a solid substance.

Uses of Crystallisation:
Crystallisation is commonly used in industries to obtain pure crystals
of substances such as alum and other salts from their solutions.

Extraction of Common Salt from Sea Water:

Sea water tastes salty because it contains dissolved salts.

Process:

Step 1:
Sea water is collected in shallow pits called salt pans.

Step 2:
Sunlight heats the water and causes evaporation.

Step 3:
As water evaporates, the dissolved salt remains behind.

Step 4:
After complete evaporation, solid crystals of common salt are obtained.

Final Answer:
Crystallisation is the process of obtaining pure solid crystals from a
supersaturated solution. Common salt is extracted from sea water by
evaporation of water in salt pans.
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