Sulfur is the second member of oxygen family and belongs to group-16 (VI A) of the periodic table.
Occurrence : Sulfur occurs in the earth’s crust to the extent of 0.05%. It occurs in the free state as well as in combined state. Sulfur occurs mainly as sulfides and sulfates. eg.
Sulfide Ores |
Sulfate Ores |
Iron pyrites (fool’s gold) – FeS2
|
Gypsum – CaSO4. 2H2O
|
Galena – PbS
|
Epsom salt – MgSO4. 7H2O
|
Copper pyrites – CuFeS2
|
Barytes – BaSO4
|
Cinnabar – HgS
|
Zinc blende – ZnS
|
Extraction of sulphur (Frasch process) : Sulphur is generally extracted from underground deposits by drilling three concentric pipes upto the beds of sulphur (700 – 1200 feet deep).
Properties of sulphur : It burns in air with, a blue flame forming SO2
, gives sulphur hexafluoride with F2
and sulphur mono chloride with CI2
, sulphides with metals like Na, Ca, Zn, Hg, Fe, Cu etc., reduces HNO3
to NO2
and
H2SO4 to
SO2 With NaOH solution on heating,
S8 + 12NaOH ——→ 4Na2S + 2Na2S2O3 + 6H2O.
It gives sodium sulphide and sodium thiosulphate, with excess of sulphur, 2Na2S + S8 ——→ 2Na2S5.
.
Uses of sulphur : It is used in the manufacture of matches, gun powder (mixture of charcoal, sulphur and potassium nitrate), explosives and fire works SO2, H2SO4
, CS2
and dyes, sulpha drugs and ointment for curing skin diseases and in the vulcanization of rubber.
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