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

Which pair of elements can form alloy?

1. Zn and Cu

2. Fe and Hg

3. Fe and C

4. C and Pt

Cupellation process is used in the metallurgy of:

1. copper

2. silver

3. lead

4. iron

Chile saltpetre is the ore of:

1. Mg

2. K

3. Na

4. Ca

Blast furnace is used in the metallurgy of:

1. Al

2. Fe

3. gold

4. Ag

Liquation is used to purify:

1. Pb

2. Sn

3. Bi

4. All

Blood haemoglobin contains:  

1. Al

2. Mg

3. Cu

4. Fe

Wolframite ore contains:

1. Zn

2. W

3. Hf

4. Au

The process in which ore is  heated in limited supply of air below its melting point  is known as:

1. Roasting

2. Calcination

3. Reduction

4. Distillation

Iron is made inactive or passive by:

1. H₃PO₄

2. conc. HNO₃

3. conc. H₂SO₄

4. dil. HNO₃