Question

27. Which Of The Following Will 1 point
Lead To Changes Which
Cannot Be Reversed? *
O
Addition of water to salt, addition of
water to cement.
O
Addition of water to cement,
addition of water to plaster of Paris.
O
Addition of water to plaster of Paris,
pouring of water on hot iron rim of a
cartwheel.
Addition of water to salt, pouring of
water on hot iron rim of a cartwheel.
1 point
28. In Which Of The Following
Statements Is Or Are​

Answer 1

Answer:

Plaster of Paris when reacts with water liberating heat through crystallization. Gypsum is produced by heating plaster of paris to about 150-degree Celsius. When the dry plaster of paris powder is mixed with water it reforms into gypsum. Depending upon the temperature gypsum converts to hemihydrate or anhydrous form.

Plaster of ParisCaSO4.21H2O+Water23H2O⟶GypsumCaSO4.2H2O

Answer 2

Answer:

O

Addition of water to cement,

addition of water to plaster of Paris.

this is the correct answer