How is Plaster of Paris (POP) prepared chemically?

Question

I need to understand the preparation process of Plaster of Paris for my NEET exam. Can someone explain the chemical preparation of POP?

NEET Faculty · Answer

Plaster of Paris is prepared by heating gypsum (CaSO₄Â·2H₂O) to a temperature of about 373K (100Â°C). The chemical reaction involved is:

CaSO₄Â·2H₂O (gypsum) â†’ CaSO₄Â·Â½H₂O (Plaster of Paris) + 1.5H₂O

This process removes three-quarters of the water content from the gypsum, resulting in the formation of Plaster of Paris.

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