Explain about the plaster of Paris and useful of it and also give examples

Explanation: 3 Marks

1. Plaster of Paris is chemically different from gypsum in terms of water of crystallisation. Gypsum has 2 moles of water per mole of CaSO₄. It can also be written as if one mole of water of crystallisation is present for two moles of CaSO₄, (2CaSO₄ . H2O). Gypsum on heating at 373 K gets converted into Plaster of Paris.

2. CaSO4.2H2O→CaSO4.(12)H2O+32H2O

Gypsum Plaster or Paris

When Plaster of Paris is mixed with water, it gets converted into gypsum.

CaSO4.(12)H2O+(32)H2O→CaSO4.2H2O

Plaster of Paris Gypsum

3. Plaster of paris is used for making statues and for setting of fractured bones by making cast around the fractured limbs.

USES:-

· Plaster of paris is used in making casts and patterns for moulds and statue.

· Plaster of paris is used as cement in ornamental casting and for making decorative materials.

· Plaster of paris is used as a fire proofing material and for making chalks.

· Plaster of pairs is used in hospitals for immobilising the affected part in case of bone fracture or strain.

· Plaster of paris (POP) is used to fill small gaps on walls & roofs.