Question

Why plaster of paris should always stored in a tight container?

Answer 1

Calcium sulphate hemihydrate ( CaSO4.1/2H2O or 2CaSO4.H2O)  is known as Plaster of Paris (POP)
The white powder of Plaster of Paris on mixing it with water changes to gypsum and sets in as a hard solid mass.
CaSO4.1/2H2O+3/2H2O→ CaSO4 .2H2O
Due to this reason Plaster of Paris  should be stored in air tight container because air contains moisture this moisture can cause the setting of plaster of Paris into hard mass gypsum. Which makes the Plaster of Paris useless.

Answer 2

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☺ Hello mate__ ❤

◾◾here is your answer...

➽Plaster of Paris (POP) should be stored in a moisture-proof container because Plaster of Paris, a powdery mass, absorbs water (moisture) to form a hard solid known as gypsum.

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Reaction :--

CaSO4.1/2 H2O + 3/2 H2O ----> CaSO4.2H2O

Here

1) CaSO4.1/2 H2O --POP

2) CaSO4.2H2O -- gypsum

I hope, this will help you

Thank you______❤

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