Answers

2015-08-23T21:04:15+05:30
Plaster of paris when kept in the presence of moisture, reacts with water present in moisture and forms GYPSUM which is a hard substance. if it forms then plaster of paris becomes useless.
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2015-08-24T20:31:56+05:30
BCOZ THIS REACTS WITH MOISTURE IN THE AIR TO FORM GYPSUM WHICH IS AN HARD MASS.
CaSO₄.1/2 H₂O +1 1/2H₂O⇒CaSO₄.2H₂O
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