Question

the property by which certain hydrated salts When left exposed to atmosphere lose their water of crystallization and crumble into powder

Answer 1

 Efflorescence : Hydrated salt when left exposed to atmosphere lose their water of crystallization and crumble down to form a powder. Such salts are known as efflorescent salt and the property is known as efflorescence. Na2CO3.10H2O, on being exposed to atmosphere, loses its water of crystallization and crumbles to form powder.

Answer 2

the property is efflorescence in which some salts wholly or partly lose their water of crystallization when their crystals are exposed to atmosphere for even a short while and then crumble into powder

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