Question

Name the product obtained when Plaster of Paris is mixed with water. State the use of the product. Give two uses of POP.

Answer 1

Hint: The Plaster of Paris mentioned in the question is chemically Calcium sulphate hemihydrate. The chemical formula is\[\left( {CaS{O_4}.\dfrac{1}{2}{H_2}O} \right)\]. It is prepared by heating a compound called gypsum where it is exposed to the temperature of 373K. At such temperature, it loses water and forms a powdery white mass called POP.

Complete answer:
Let us see the reaction between Plaster of Paris and water. The reaction is as follows:
\[CaS{O_4}\dfrac{1}{2}{H_2}O + 1\dfrac{1}{2}{H_2}O \to CaS{O_4}.2{H_2}O\]
The product formed by the above reaction is Gypsum which is chemically Calcium sulphate dihydrate. It is dihydrate as it contains two water molecules whereas POP is hemihydrate. It has a wide range of uses. It is used as a soil amendment where it can supply both Calcium and Sulphur to the soil thus improving plant growth. It is also used in the preparation of Plaster of Paris, cement, tiles and many others. Some varieties of gypsum are also used for ornamental purposes. Plaster of Paris has its main use in newly constructed houses where a coating of POP is done before painting the walls. It is also used as casting material. In the hospitals it is used by orthopedicians where they use this to heal the fractures bones. This is all about POP and its uses.

Note:
POP has got its name as abundant amounts of gypsum are found in and around Paris. Gypsum is in turn used in the preparation of Plaster of Paris. The dehydrated form of Gypsum is called POP. When gypsum is subjected to heat at \[{120^ \circ }C\].
The water is removed and a hemihydrate known as POP is formed.