The chemical reaction that involves roasting process is

• Fe₂O₃ + 3CO → 2Fe + 3CO₂

• 2Al + Fe₂O₃ → 2Fe + Al₂O₃

• 2ZnS + 3O₂ → 2ZnO + 3SO₂

• FeO + SiO₂ → FeSiO₃

Which one of the following oxides is reduced by water gas to obtain the metal during its extraction?

• NiO

• ZnO

• WO₃

• Fe₂O₃

Which of the following is not added durig the extraction of silver by cyanide process?

• NaCN

• Air

• Zn

• Na₂S₂O₃

What is the role of limestone during the extraction of iron from haematite ore?

• Leaching agent

• Oxidising agent

• Reducing agent

• Flux

Which of the following process involve heating?

• Calcination

• Smelting

• Roasting

• Levgation

Which of the following is a carbonate ore?

• Cuprite

• Siderite

• Zincite

• Bauxite

Copper matte contains

• CuO, FeS

• Cu₂S, FeS

• CuO, Cu₂S

• Cu₂S, FeO

Which of the following is not an ore of lead?

• Galena

• Anglesite

• Calamine

• Cerrusite

An example of halide ores is

• galena

• bauxite

• cinnabar

• cryolite

70.

After partial roasting the sulphide of copper is reduced by

• reduction by carbon

• electrolysis

• self-reduction

• cyanide process