What is the chemical formula of Plaster of Paris?
A
CaSO<sub>4</sub>.H<sub>2</sub>O
B
CaSO<sub>4</sub>.2H<sub>2</sub>O
C
CaSO<sub>4</sub>
D
CaSO<sub>4</sub>.$$\frac{1}{2}$$H<sub>2</sub>O
Correct Answer: CaSO<sub>4</sub>.$$\frac{1}{2}$$H<sub>2</sub>O