JEE Questions for Chemistry General Principles And Processes Of Isolation Of Elements Quiz 1 - MCQExams.com

1.  Argentite (Ag₂S)
2.  Galena (PbS)
3.  Chalcocite (Cu₂S)
4.  Copper pyrite (chalco pyrite) [CuFeS₂]
5.  Cassiiterite (SnO₂)
6.  Dolomite (CaMg(CO₃)₂)
7.  Bauxite (Al(OH)₃)

∴ Sulphide containing ores are Ag, Cu, Pb.

Thermite process is very useful for the welding of broken metal parts. When Aluminimum powder reacts with iron oxide or chromium oxide, a large amount of heat is released and about a temperature of 3500^oC is attained which is enough to weld broken metallic parts.

The principle ore of copper is copper pyrite (CuFeS₂) and copper is extracted from this ore. 

Froth flotation method is used for the concentration of sulphide ores. The method is based on the preferential wetting properties with the frothing agent and water. In the given options, Galena (PbS) being a sulphide ore is concentrated by froth floatation process.

The chief impurity present in red bauxite is Fe₂O₃ (ferrite or ferric oxide).

Siderite is a mineral composed of iron (II) carbonate (FeCO₃).

Gravity separation technique is used where iron ore (hematite) bearing minerals are free from associated gangue materials. The specific gravity of iron bearing minerals is usually higher than the specific gravity of gangue materials. Effectiveness efficiency of the gravity separation depends largely on to proper crushing and sizing of the ore so as to ensure a proper size feed to the gravity separation equipment and also removal of slime from the equipment.

Consider the chemical composition of the given compounds,
1) Cuprite → Cu₄O
2) Chalocie → Cu₂S
3) Chalcopyrite → CuFeS₂
4) Malachite → Cu(OH)₂ . CuCO₃
Hence Chalcopyrite contains both iron and copper.

All the given compounds except CuFe₂S₂ will gives copper directly on heating with But heating or Roasting converts CuFe₂S₂ into Cu₂S and FeO (removed as a slag) and Cu₂S and FeS is then obtained as copper matte.
  The matte ion reaction with hot compressed are gives FeO and Cu₂O . Cu₂O then reduce the Cu₂S to Cu

Slag is the fusible compound formed by the combination of flux and gangue.

i.e., CaO + SiO₂→CaSiO₃

     Flux    Gangue       Slag

AThe temperature of the slag zone in the metallurgy of iron using blast furnace is 800⁰C – 1000⁰C.

Blister copper, a matte of from 96 to 99 percent copper with 1% of impurities, having a blistered surface after smelting because of gases generated during solidification.

2Cu₂ O  + Cu₂ S → 6Cu  +  SO₂

Cuprous sulphide brings about reduction of cuprous oxide. This reaction takes place in bessemer converter during metallurgy of copper.

Hydrometallurgy is a method for obtaining metals from their ores. It is a technique within the field of extractive metallurgy involving the use of aqueous chemistry for the recovery of metals from ores, concentrates, and recycled or residual materials. Gold is extracted by hydrometallurgical process, based on its property to form complexes which are water soluble.