a. The compound which is prepared from gypsum which has the property of hardening when mixed with proper quantity of water is called plaster of Paris having the formula - CaSO4.\(\frac12\)H2O.
b. The chemical equation for the preparation of plaster of Paris is: -

Plaster of Paris is prepared by heating gypsum at 373K.
c. One of the important use of plaster of Paris is that it is used by doctors as a plaster for supporting fractured bones in the right position