A) \[CaS{{O}_{4}}.5{{H}_{2}}O\]
B) \[CaS{{O}_{4}}.3{{H}_{2}}O\]
C) \[CaS{{O}_{4}}.2{{H}_{2}}O\]
D) \[CaS{{O}_{4}}.1/2{{H}_{2}}O\]
Correct Answer: C
Solution :
When powdered plaster of Paris mixed with water It takes up the water of crystallisation and forms a Plastic mass that gets converted into hard solid (gypsum) within 6 to 15 min. \[\underset{\text{Plaster}\,\text{of}\,\text{Paris}}{\mathop{CaS{{O}_{4}}.\frac{1}{2}{{H}_{2}}O}}\,\xrightarrow{{{H}_{2}}O(Setting)}\underset{\text{Orthorhombic}}{\mathop{CaS{{O}_{4}}.2{{H}_{2}}O}}\,\] \[\xrightarrow{\text{Harderning}}\underset{\text{Monoclinic}\,\text{(gypsum)}}{\mathop{CaS{{O}_{4}}.2{{H}_{2}}O}}\,\]You need to login to perform this action.
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