What is the most correct reason for keeping plaster of Paris away from moisture?
Answer and explanation
Correct answer: It can set on absorbing moisture
Plaster of Paris, or calcium sulphate hemihydrate, reacts with water and changes back into gypsum, which is hard. Moisture from air can therefore begin the setting process before the material is needed. Option A is correct because premature setting makes the powder unusable. The other options describe chemically impossible changes: it does not become sugar, gas, or metal. Hence it must be stored in a dry, airtight container.
Frequently asked questions
What is the correct answer to this question?
It can set on absorbing moisture
Why is this the correct answer?
Plaster of Paris, or calcium sulphate hemihydrate, reacts with water and changes back into gypsum, which is hard. Moisture from air can therefore begin the setting process before the material is needed. Option A is correct because premature setting makes the powder unusable. The other options describe chemically impossible changes: it does not become sugar, gas, or metal. Hence it must be stored in a dry, airtight container.
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.
