Question

A compound which is prepared from gypsum has the property of hardening when mixed with proper quantity of water. Identify the compound. Write the chemical equation to prepare the compound. Mention one important use of the compound.

Answer 1

1. Plaster of Paris $\left({\mathrm{CaSO}}_4·{\displaystyle \frac{1}{2}}{H}_{2}O\right)$ is formed when Gypsum $({\mathrm{CaSO}}_2·2H_{2}O)$ by heating carefully at a very high temperature which is nearly about 373K.
2. It has the property of hardening when it is mixed with the proper quantity of water.
3. After heating the gypsum, if there is any addition of water it changes the back to gypsum.

Chemical equation:

${\mathrm{CaSO}}_4·2{\mathrm{H}}_2\mathrm{O}\to {\mathrm{CaSO}}_4·{\displaystyle \frac{1}{2}}{\mathrm{H}}_2\mathrm{O}+{\displaystyle \frac{1}{2}}{\mathrm{H}}_2\mathrm{O}$

Important uses of Plaster of Paris:

When any bones are fractured, it helps in setting these fractured bones.

Thus, the compound is Plaster of Paris.