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Plaster of Paris has a remarkable proper...

Plaster of Paris has a remarkable property of setting with water. On mixing with one-third its weight of water, it forms a plastic mass that sets into a hard mass of interlocking crystals of ____ within 5 to 15 min.

A

`CaSO_(4).2H_(2)O`

B

`CaSO_(4).H_(2)O`

C

`CaSO_(4).3H_(2)O`

D

`CaSO_(4).4H_(2)O`

Text Solution

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The correct Answer is:
A
Due to this reaction, it is called plaster. The addtionof common salt accelerates the rate of setting,while a little borax or alum reduced it. The setting of POP is believed to be due to dehydration and its reconversioninto gypsum
`2CaSO_(4).(1)/(2)H_(2)O+3H_(2)Oto2CaSO_(4).2H_(2)O`
During the process of setting slight expansion (1%) in volume occurs. As a result it can take up the shape and impression of the mould in which it is put.
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R SHARMA-THE S BLOCK ELEMENTS-Follow-up Test 11
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  5. Calcium carbonate, commonly called limestone, is prepared by passing C...

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  6. Which of the following in incorrect for CaCO(3) ?

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  7. Calcium carbonate along with is used as a flux in the extraction of m...

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  8. Calcium carbonate is used as (i) a filler in cosmetics (ii) a cons...

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  9. Plaseter of Paris, a white powder, is

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  10. Plaster of Paris is obtained when gypsum is heated to

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  11. Plaster of Paris has a remarkable property of setting with water. On m...

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  12. The raw materials for the manufacture of Portland cement (or just ceme...

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  13. Cement is essentially a finely powdered mixture of calcium silicates a...

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  19. The calcium concentration in plasma is regulated at about mg L^(-1).

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