Which of the following pairs of metals is purified by van Arkel method?

• Zr and Ti

• Ag and Au

• Ni and Fe

• Ni and Fe

In the extraction of copper from its sulphide ore, the metal finally obtained by the reduction of cuprous oxide with 

• Iron (II) sulphide

• Carbon monoxide

• Copper (I) sulphide

• Copper (I) sulphide

Identify the alloy containing a non-metal as a constituent in it.

• Invar

• Steel

• Bell metal

• Bell metal

Which of the following elements is present as the impurity to the maximum extent in the big iron?

• Carbon

• Silicon

• Phosphorus

• Phosphorus

In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with

• Copper (I) sulphide (Cu₂S)

• sulphur dioxide (SO₂)

• Iron sulphide (FeS)

• Iron sulphide (FeS)