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

In the cyanide extraction process of silver from argentite ore, the oxidizing and reducing agents used for:

1. O₂ and CO respectively

2. O₂ and  Zn dust respectively

3. HNO₃ and Zn dust respectiely

4. HNO₃ and CO respectively

Name the metal M which is extracted on the basis of following reactions,

4M+8CN^-+2H₂O+O₂$\to$4[M(CN)₂]^-+4OH^-

2[M(CN)₂]^-+Zn$\to$[Zn(CN)₄]^2-+2M

1. nickel

2. silver

3. copper

4. mercury

Nickel is purified by thermal decomposition of its:

1. Hydride

2. Chloride

3. Azide

4. Carbonyl

Coating of zinc on iron objects is commonly known as:

1. electroplating

2. surface coating

4. galvanising

4. sheardising

The second most common element on the earth is:

1. silicon

2. hydrogen

3. nitrogen

4. oxygen

Alloy is an example of:

1. gel

2. aerosol

3. solid sol

4. emulsion

Which element is purified by Zone refining?

1. Ge

2. Ge and Si

3. Si

4. None

Which is not a mineral?

1. Mica

2. Peat

3. Quartz

4. Felspar