Question

plaster of Paris hardens by a) giving of Co2 b) changing into caco3 c)combining with water d) giving out water

Answer 1

Answer:

Plaster of Paris hardens by combining with water.

Explanation:

Plaster of Paris is a salt of calcium metal which is also called as calcium sulfate hemihydrate.

The chemical formula of plaster of Paris is $\bold{\mathrm{CaSO}_{4} \cdot \frac{1}{2} \mathrm{H}_{2} \mathrm{O}}$. It is formed by the intense heating of gypsum that is also a salt of calcium.  

When we add water to plaster of Paris it becomes soften and forms a paste. This paste becomes harden after some time because of formation of string hydrogen bonding between molecules of plaster of Paris and water.  

Answer 2

Option (c) is the correct answer

Plaster of Paris hardens by combining with water

Explanation:

• Plaster of Paris is also known as Gypsum plaster.
• The chemical formula of Plaster of Paris is $CaSO4.\frac{1}{2} H2O.$
• Chemical reaction how Plaster of Paris works :-
• Plaster of Paris is mixed with water in the process for action.
• Plaster of Paris becomes hard when mixed with water.
• Here a crystallization reaction occurs with Plaster of Paris  and water, which leads to the formation of orthorhombic calcium sulphate dihydrate.
• Release of heat occurs which causes the water present to evaporate.
• In this process a hard mass which is monoclinic calcium sulphate dihydrate or gypsum is formed.
• It is the final product of setting of plaster of Paris.
• In about half an hour a hard mass is formed when water is added to plaster of Paris.

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