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2. s-Block Elements eLearn.Punjab

4LiNO3(s) → 2Li2O (s) + 4NO2 (s) + O2 (g)
2 Mg(NO3)2 (s) → 2MgO (s) + 4NO2 (g) + O2 (g)
2Ca(NO3)2 (s) → 2CaO (s) + 4NO2 (g) + O2 (g)
2NaNO3(s) → 2NaNO2 (s) + O2 (g)

v) Sulphates

All the alkali metals give sulphates and they are all soluble in water.
The solubilities of sulphates of alkaline earth metals, gradually
decrease down the group. BeSO4 and MgSO4 are fairly soluble in water.
CaSO4 is slightly soluble, while SrSO4 and BaSO4 are almost insoluble.

Calcium sulphate occurs in nature as gypsum CaSO4.2H2O. When
it is heated above 100°C, it loses three quarters of its water of
crystallization, giving a white powder called’ Plaster of Paris.

2CaSO4 . 2H2O → (CaSO4 )2 . H2O + 3H2O

Gypsum Plaster of Paris

2.3 COMMERCIAL PREPARATION OF SODIUM BY DOWNS
CELL

Most of sodium metal is produced by the electrolysis of fused
sodium chloride. Since the melting point of sodium chloride
is 801°C, some calcium chloride is added to lower its melting
point and to permit the furnace to operate at about 6000C.

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