Silver obtained by argentiferrous lead is purified by:

1. distillation

2. froth floatation

3. cupellation

4. reacting with KCN

The following equation represents a method of purification of nickel by,

Ni + 2CO $\stackrel{320\mathrm{K}}{\to }$Ni(CO)₄ $\stackrel{420\mathrm{K}}{\to }$Ni +4CO this method is:

impure                                 pure

1. Cupellation

2. Mond's process

3. Van Arkel method

4. Zone refining

Cupellation process is used in the metallurgy of:

1. copper

2. silver

3. lead

4. iron

Which substance is used as basic refractory material in furnace?

1. Al₂O₃

2. SiO₂

3. CaO

4. Fe₂O₃

Which element is purified by Zone refining?

1. Ge

2. Ge and Si

3. Si

4. None

Nickel is purified by thermal decomposition of its:

1. Hydride

2. Chloride

3. Azide

4. Carbonyl

In Serpek's process , by product obtained in the purification of bauxite is:

1. Al₂O₃

2. N₂

3. NH₃

4. none

CO is used in the metallurgy of:

1. Cu

2. Ni

3. Cr

4. Pt

Which of the following is leached with NaCN?

1. Ore of Al

2. Ore of Cu

3. Ore of Ag

4. Ore of Zn

Vapour phase refining can be carried out in case of 

1. Ni

2. Zr

3. Ti

4. All of these