Why is plaster of Paris kept away from moisture?
Answer and explanation
Correct answer: It can take up water and turn into hard gypsum
Plaster of Paris is calcium sulfate hemihydrate, CaSO₄·½H₂O. Moisture supplies water that converts it into gypsum, calcium sulfate dihydrate, according to CaSO₄·½H₂O + 1½H₂O → CaSO₄·2H₂O. This hydration causes the material to set and become hard. Consequently, exposure to moisture can spoil its usefulness during storage, so it is kept in moisture-proof packaging. Option A is correct.
Frequently asked questions
What is the correct answer to this question?
It can take up water and turn into hard gypsum
Why is this the correct answer?
Plaster of Paris is calcium sulfate hemihydrate, CaSO₄·½H₂O. Moisture supplies water that converts it into gypsum, calcium sulfate dihydrate, according to CaSO₄·½H₂O + 1½H₂O → CaSO₄·2H₂O. This hydration causes the material to set and become hard. Consequently, exposure to moisture can spoil its usefulness during storage, so it is kept in moisture-proof packaging. Option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
