Q. Plaster of Paris on making paste with little water sets to hard mass due to formation of
A) $CaSO_{4}$
B) $CaSO_{4}.\ 1/2\ H_{2}O$
C) $CaSO_{4}\ .\ H_{2}O$
D) $CaSO_{4}\ .\ 2H_{2}O$
Explanation
(d)
Plaster of Paris is a whit powder. It changes into a hard mass called gypsum on mixing with water. There is a slight increase in volume during this process.
$CaSO_{4}\ .\frac{1}{2}H_{2}O + 1\frac{1}{2}H_{2}O\ \rightarrow CaSO_{4}\ .\ 2H_{2}O + Heat$
Plaster of Paris gypsum
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.