Question

what is plaster of paris how it is obtained from gypsum​

Answer 1

Answer:

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Plaster of Paris:

Plaster of Paris also known as Calcium sulphate hemihydrate, it is a dry white powdery substance.

Preparation:

It is prepared by control heating of Gypsum (CaSO₄ . 2H₂O) at 373 K or 100°C, gypsum loses its water molecules and it forms Calcium Sulphate HemiHydrate i.e. Plaster of paris.

Chemical reaction:

$\sf CaSO_{4}\;.\;2\;H_{2}O\xrightarrow{\sf \Delta\; at \;373 K} CaSO_{4}\;.\;\dfrac{1}{2}\;H_{2}O$

                         (OR)

$\sf CaSO_{4}\;.\;2\;H_{2}O\xrightarrow{\sf \Delta\; at \;373 K} 2\;CaSO_{4}\;.\;H_{2}O$

Uses:

1) It is used to make sculptures and metal castings.

2) It gives support to the fractured Bones.

3) It is used in laboratories to seal the experiment apparatus.

4) It is also good fire resistant.

5) It is also used in radio therapy.

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Answer 2

Answer:

Plaster of paris is a hemihydrate of

calcium sulphate (CasO4 . 1/2 H20).

Plaster of paris is obtained by heating

gypsum to 393K

2 (CasO4.2H20) 2 (CaSO4). H2O +

3H20.

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