What is the chemical name of plaster of Paris?
Answer and explanation
Correct answer: Calcium sulphate hemihydrate
The governing concept is the preparation and hydration of salts. Plaster of Paris is calcium sulphate hemihydrate, CaSO₄·½H₂O. It is prepared by carefully heating gypsum, CaSO₄·2H₂O, to remove part of its water of crystallisation. When water is added, plaster of Paris changes back into gypsum and sets into a hard mass. Washing soda, common salt, and calcium carbonate are different compounds, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
Calcium sulphate hemihydrate
Why is this the correct answer?
The governing concept is the preparation and hydration of salts. Plaster of Paris is calcium sulphate hemihydrate, CaSO₄·½H₂O. It is prepared by carefully heating gypsum, CaSO₄·2H₂O, to remove part of its water of crystallisation. When water is added, plaster of Paris changes back into gypsum and sets into a hard mass. Washing soda, common salt, and calcium carbonate are different compounds, so 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.
