Question
Identify the correct statement.
A.
Gypsum is obtained by heating plaster of Paris
B.
Plaster of Paris can be obtained by hydration of gypsum
C.
Plaster of Paris is obtained by partial oxidation of gypsum
D.
Gypsum contains a lower percentage of calcium than plaster of Paris
Answer :
Gypsum contains a lower percentage of calcium than plaster of Paris
Solution :
The formula of gypsum is $$CaS{O_4} \cdot 2{H_2}O$$ and that of plaster of Paris is $${\left( {CaS{O_4}} \right)_2} \cdot 2{H_2}O,$$ so the percentage of $$Ca$$ in plaster of Paris is more than gypsum.