Q. The difference of water molecules in gypsum and plaster of Paris is
A) $\frac{5}{2}$
B) 2
C) $\frac{1}{2}$
D) $1\frac{1}{2}$
Explanation
(d)
Formula of gypsum $= CaSO_{4}.\ 2H_{2}O$
Formula of plaster of Paris $= CaSO_{4}\ .\frac{1}{2}H_{2}O$
Difference of water molecule$= 2H_{2}O\ –\frac{1}{2}H_{2}O$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 1\frac{1}{2}H_{2}O$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.