Question

What is dead burnt plaster?

Answer 1

Dead Burnt Plaster:

1. The anhydrous form of Calcium sulfate(CaSO₄) is called dead burnt plaster.
2. It is called dead burnt because when water is added to the anhydrous salt it does not convert back to gypsum and thus is not useful.
3. When Plaster of Paris is heated over 373K dead burnt plaster is formed.
4. $\underset{\mathrm{Plater}\mathrm{of}\mathrm{Paris}}{{\mathrm{CaSO}}_4.\frac{1}{2}{\mathrm{H}}_2\mathrm{O}\left(\mathrm{s}\right)}\stackrel{\mathrm{T}>373\mathrm{K}}{\to }\underset{\mathrm{Dead}\mathrm{burnt}\mathrm{plaster}}{{\mathrm{CaSO}}_4\left(\mathrm{s}\right)}+\frac{1}{2}{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

Uses of Dead burnt plaster:

1. Used to give plaster finishing.
2. Used in place of high friction and high traffic.