Consider the below statements and identify the correct answer.

Statement-I: Plaster of Paris has a very remarkable property of setting into hard mass on wetting with water.

Statement-II: Plaster of Paris is used in chemistry laboratories for sealing air gaps in apparatus where air tight arrangement is required.

The correct answer Both the statements are true.

Key Points:

• Plaster of Paris's characteristics:
  • When wetted with water or exposed to a mixture and left to dry, it solidifies into a hard mass.
  • The substance is a fine white powder.
• Applications:
  • In order to assure proper healing, it is used in hospitals to fix broken bones.
  • Due to its setting property, it is used to make toys, decorative items, inexpensive ornaments, cosmetics, blackboard chalk, and statue casts.
  • It serves as a fire-retardant substance.
  • It is used in chemistry labs to close air gaps in equipment when an airtight arrangement is necessary. 

Additional Information:

• Calcium sulphate hemihydrate is what makes plaster of Paris (calcium sulphate half-hydrate).
• CaSO₄.12H₂O is the plaster of Paris's chemical formula.
• Gypsum (CaSO4.2H2O) is heated to a temperature of 100 °C to prepare it.
• Gypsum loses three-fourths of its water of crystallization when heated to a temperature of 100°C (373K), creating Plaster of Paris.