Plaster of Paris hardens by-

Correct option is D

The correct answer is (d) Combining with water.
· Plaster of Paris (CaSO₄·½H₂O) hardens when it combines with water. When mixed with water, it undergoes a chemical reaction to form gypsum (CaSO₄·2H₂O). This process is called hydration, and it results in the hardening of the plaster.
The reaction is as follows:
CaSO₄.½H₂O+1.5H2O→CaSO4 2H₂O
This transformation turns the soft plaster into a hard and solid form.
Information Booster:
· Plaster of Paris: A quick-setting gypsum-based material commonly used for casting, construction, and medical purposes.
· Gypsum: The end product when Plaster of Paris combines with water, resulting in a hard, solid material.
· Hydration process: Plaster of Paris hardens as it absorbs water and changes into gypsum.
· Uses: Plaster of Paris is used for making sculptures, medical casts, and in building materials.