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प्रश्न
Dead burnt plaster is ______.
विकल्प
CaSO4
\[\ce{CaSO4 . 1/2 H2O}\]
CaSO4.H2O
CaSO4.2H2O
उत्तर
Dead burnt plaster is CaSO4.
Explanation:
Plaster of Paris is prepared by heating gypsum at 120°C
\[\ce{\underset{Gypsum}{2CaSO4 . 2H2O} -> (\underset{Plaster of Paris}{CaSO4)2 . H2}O + 3H2O}\]
On heating plaster of Paris at 200°C, it forms anhydrous calcium sulphate, i.e., dead plaster which has no setting property as it absorbs water very slowly.
\[\ce{CaSO4 . 1/2 H2O ->[200°C] \underset{Anhydride}{CaSO4} ->[1100°C] CaO + SO3}\]
APPEARS IN
संबंधित प्रश्न
Describe the importance of the cement.
Describe the importance of the plaster of paris.
Suspension of slaked lime in water is known as ______.
Match the elements given in Column I with the properties mentioned in Column II.
| Column I | Column II |
| (i) Li | (a) Insoluble sulphate |
| (ii) Na | (b) Strongest monoacidic base |
| (iii) Ca | (c) Most negative EΘ value among alkali metals. |
| (iv) Ba | (d) Insoluble oxalate |
| (e) 6s2 outer electronic configuration |
When water is added to compound (A) of calcium, solution of compound (B) is formed. When carbon dioxide is passed into the solution, it turns milky due to the formation of compound (C). If excess of carbon dioxide is passed into the solution milkiness disappears due to the formation of compound (D). Identify the compounds A, B, C and D. Explain why the milkiness disappears in the last step.
A substance absorbs \[\ce{CO2}\] and violently reacts with water. That substance is ______.
Initial setting of cement is mainly due to ______.
What are the products formed in sequence when excess of CO2 is passed in slaked lime?
The commercial name for calcium oxide is ______.
Which of the following on thermal decomposition yields a basic as well as acidic oxide?
