Question

Plaster of Paris should be stored in a moisture-proof container. Explain why?

Answer 1

Plaster of Paris in contact with moisture(water) changes to solid hard mass, gypsum. Therefore, it gets wasted. Hence it should be stored in moisture proof containers.

Answer 2

Hey Dear,

Formula for Plaster of Paris is CaSO4.½H2O.

● Plaster of Paris should be stored in a moisture-proof container because -

• Moisture contains water molecules.
• Plaster of Paris readily reacts with water vapor from moisture.
• When Plaster of Paris reacts with water, it becomes absolutely hard after some time due to formation of gypsum.

CaSO4.½H2O + 3/2 H2O --> CaSO4.2H2O

• This rock hard gypsum is not usable.
• Hence, PoP should be stored in a moisture-proof container.

Thanks dear.