The main difference between gypsum and plaster of Paris is related to what?
Answer and explanation
Correct answer: Amount of water of crystallisation
Gypsum is calcium sulphate dihydrate, CaSO₄·2H₂O. On controlled heating, it loses part of its water of crystallisation and forms plaster of Paris, calcium sulphate hemihydrate, CaSO₄·½H₂O. Thus their principal difference is the amount of chemically combined water, so option A is correct. Metallic shine, chlorine smell, and litmus colour are not the defining chemical differences between these two calcium sulphate forms.
Frequently asked questions
What is the correct answer to this question?
Amount of water of crystallisation
Why is this the correct answer?
Gypsum is calcium sulphate dihydrate, CaSO₄·2H₂O. On controlled heating, it loses part of its water of crystallisation and forms plaster of Paris, calcium sulphate hemihydrate, CaSO₄·½H₂O. Thus their principal difference is the amount of chemically combined water, so option A is correct. Metallic shine, chlorine smell, and litmus colour are not the defining chemical differences between these two calcium sulphate forms.
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.
