what happens to the 1 1/2 water molecule after plaster of paris is formed from the gypsum.
Plaster of Paris is obtained from Gypsum by, heating it, where gypsum looses 1(1/2) molecule of water of crystallization and it is lost in the gaseous state to the environment.
CaSO4.2H2O → CaSO4.1/2H2O + 1 1/2H2O