Chemistry - Complete s-block Question with Solution | TestHub

Gypsum (CaSO₄·2H₂O) on heating at $120-130^{\circ }\mathrm{C}$ undergoes partial dehydration to form Plaster of Paris, which is calcium sulfate hemihydrate (CaSO₄·½H₂O).

The chemical reaction is:

$$\mathrm{CaS}{\mathrm{O}}_4\cdot 2{\mathrm{H}}_2\mathrm{O}\stackrel{120-130^{\circ }\mathrm{C}}{\to }\mathrm{CaS}{\mathrm{O}}_4\cdot \frac{1}{2}{\mathrm{H}}_2\mathrm{O}+\frac{3}{2}{\mathrm{H}}_2\mathrm{O}$$