The correct answer is Plaster of Paris. Key Points - Preparation of Plaster of Paris doesn't require the use of NaCl. - It is simply obtained by heating gypsum (CaSO.2H O) at 120∘C in a rotary kiln. - Reaction involved: 2(CaSO4⋅2H2O)⟶2(CaSO4)⋅H2O+2H2O. (Gypsum) & (Plaster of Paris) (Water) - It turns in solid mass when mixed with water and hence used for plasterwork.
