Question

Dead burn plaster is

• A. $CaSO _{4} \cdot 2 H _{2} O$
• B. $MgSO _{4} \cdot 7 H _{2} O$
• C. $CaSO _{4} \cdot \frac{1}{2} H _{2} O$
• D. $CaSO _{4}$

Answer 1

Answer: (D)

When plaster of Paris is heated above $393\, K$ its water of crystallization is lost and the leftover anhydrous calcium sulphate $CaSO _{4}$ is called the dead burnt plaster.