. Why is formula of Plaster of Paris written as
CaSO4.1/2H2O ? How is it possible to have half a water molecule attached to CaSO4 ?
Ans: Plaster of Paris is written as CaSO4.1/2H2O because two formula units of CaSO4 share one molecule of water i.e., 2CaSO4.H2O or CaSO4.1/2H2O.