Plaster of Paris when mixed with the correct amount of water sets into a solid mass due to the forma — s Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Plaster of Paris is calcium sulfate hemihydrate, (CaSO4)2.H2O or CaSO4.0.5H2O. Step 2: When mixed with water, it hydrates to form a plastic mass which quickly sets into a hard solid mass of gypsum. Step 3: The chemical reaction is: CaSO4.0.5H2O + 1.5H2O -> CaSO4.2H2O (gypsum). Therefore, setting is due to the formation of CaSO4.2H2O, which corresponds to option (c).