Why is plaster of Paris kept away from moisture in a closed container?
Answer and explanation
Correct answer: It can absorb moisture and change into gypsum
Plaster of Paris is calcium sulphate hemihydrate, CaSO4·1/2H2O. It reacts with water to form gypsum, CaSO4·2H2O: CaSO4·1/2H2O + 1 1/2H2O → CaSO4·2H2O. This hydration makes the material set and harden, so unwanted moisture can spoil its storage and handling properties. It does not form an acid, release chlorine, or produce sodium carbonate. Therefore A is correct.
Frequently asked questions
What is the correct answer to this question?
It can absorb moisture and change into gypsum
Why is this the correct answer?
Plaster of Paris is calcium sulphate hemihydrate, CaSO4·1/2H2O. It reacts with water to form gypsum, CaSO4·2H2O: CaSO4·1/2H2O + 1 1/2H2O → CaSO4·2H2O. This hydration makes the material set and harden, so unwanted moisture can spoil its storage and handling properties. It does not form an acid, release chlorine, or produce sodium carbonate. Therefore 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.
