Gypsum forms plaster of Paris on controlled heating. What problem can occur on excessive heating?
Answer and explanation
Correct answer: Too much water may be removed and useful hemihydrate form may be spoiled
Gypsum is calcium sulfate dihydrate, CaSO4·2H2O. Controlled heating removes one and a half molecules of water to form plaster of Paris, calcium sulfate hemihydrate, CaSO4·1/2H2O. Excessive heating can remove the remaining water and produce anhydrous calcium sulfate, which does not set properly with water. Thus option A is correct.
Frequently asked questions
What is the correct answer to this question?
Too much water may be removed and useful hemihydrate form may be spoiled
Why is this the correct answer?
Gypsum is calcium sulfate dihydrate, CaSO4·2H2O. Controlled heating removes one and a half molecules of water to form plaster of Paris, calcium sulfate hemihydrate, CaSO4·1/2H2O. Excessive heating can remove the remaining water and produce anhydrous calcium sulfate, which does not set properly with water. Thus 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.
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