Question

Why does Anhydrous calcium chloride turn into a colourless solution when exposed to air?

Answer 1

Hint: Anhydrous is a substance, especially a crystalline compound containing no water. So, anhydrous calcium chloride is a crystalline compound of calcium chloride having no content of water.

Complete step by step answer:
First of all, you need to know about what is a deliquescence and deliquescent substances? Deliquescence is the process by which a chemical substance absorbs moisture from the atmosphere and dissolves in it. So, deliquescent substances will absorb moisture from the atmosphere. Calcium chloride is a deliquescent substance. If anhydrous calcium chloride is exposed to air, it will absorb sufficient water from the air to allow it to dissolve. After a short while, instead of a white lump, you will have a pool of clear liquid.
So, anhydrous calcium chloride is a deliquescent that is why it turns colourless when exposed to air.

Additional Information:
Anhydrous Calcium Chloride is a purified inorganic salt produced by removing water from a naturally occurring brine solution.
Anhydrous Calcium Chloride mini-pellets are commonly used to formulate high density, solids-free drilling fluids for the oil and gas industry.
This is also used in concrete acceleration and dust control applications.
Calcium Chloride is included as an additive in plastics and in fire extinguishers, in wastewater treatment as a drainage aid, in blast furnaces as an additive to control scaffolding, and in fabric softener as a thinner.

Note: Solid Calcium Chloride is both hygroscopic and deliquescent. This means that the product can absorb moisture from the air, even to the point of converting to liquid brine. For this reason, solid Calcium Chloride should be protected from excessive exposure to moisture to product quality while in storage.