Why is Plaster of Paris kept away from moisture?
Answer and explanation
Correct answer: Because it can take up water and set into hard gypsum
Plaster of Paris is calcium sulfate hemihydrate, CaSO4·1/2H2O. It reacts with water and changes back into gypsum, CaSO4·2H2O, forming a hard solid mass. This setting reaction is useful when making casts, but unwanted moisture can make the powder set during storage and spoil it before use. Hence option A is correct; it does not become acid, sugar, or burn in moisture.
Frequently asked questions
What is the correct answer to this question?
Because it can take up water and set into hard gypsum
Why is this the correct answer?
Plaster of Paris is calcium sulfate hemihydrate, CaSO4·1/2H2O. It reacts with water and changes back into gypsum, CaSO4·2H2O, forming a hard solid mass. This setting reaction is useful when making casts, but unwanted moisture can make the powder set during storage and spoil it before use. Hence option A is correct; it does not become acid, sugar, or burn in moisture.
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.
