​What is the chemical formula Plaster of Paris?

Correct option is D

​The correct answer is (d) 2CaSO₄·H₂O

Explanation:

Plaster of Paris (POP) is chemically known as Calcium Sulfate Hemihydrate and has the chemical formula:

                                                                 $$2\text{CaSO}_4 \cdot \text{H}_2\text{O}$$​​

It is obtained by heating Gypsum (CaSO₄·2H₂O) at 150°C (373K), which removes part of the water content to form Plaster of Paris.

                                        $$\text{CaSO}_4 \cdot 2\text{H}_2\text{O} \xrightarrow{\text{Heat } (150^\circ C)} 2\text{CaSO}_4 \cdot \text{H}_2\text{O} + 3\text{H}_2\text{O}$$​​

• POP is soft when mixed with water, but it hardens on drying due to rehydration.
• It is widely used in sculptures, medical casts, moldings, and construction work.

Information Booster:

Uses of Plaster of Paris (POP):

• Construction – Used for wall coatings, false ceilings, and decorative moldings.
• Medical Applications – Used for making orthopedic casts to set fractured bones.
• Sculpture & Art – Used in making statues and idols.
• Dentistry – Used in making dental molds.