Question

The difference in number of water molecules in gypsum and plaster of paris is:

• A. 5/2
• B. 2
• C. 1/2
• D. 3/2

Answer 1

The correct option is D 3/2

Gypsum is $CaS{O}_4.2H_{2}O$ and Plaster of paris is $CaS{O}_4.0.5H_{2}O$. The difference in number of water molecules is $=\frac{3}{2}$ or $1\frac{1}{2}$