Roasting is generally carried out in case of :

(1) oxide ores

(2) sulphide ores

(3) silicate ores

(4) carbonate ores

Alloy is an example of:

(1) gel

(2) aerosol

(3) solid sol

(4) emulsion

Nickel is purified by thermal decomposition of its:

(1) Hydride

(2) Chloride

(3) Azide

(4) Carbonyl

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

2[M(CN)₂]^- + Zn$\to$[Zn(CN)₄]^2- + 2M

The metal M in above-mentioned reaction is:

1. Nickel

2. Silver

3. Copper

4. Mercury

In the metallurgy of copper, the slag is 

1. FeSiO₃

2. CaCO₃

3. CaSiO₃

4. CaO

Galena contains ZnS with PbS. Which of the following is used as depressant to stop ZnS to come with foam?

1. NaCN

2. Aniline

3. Pine Oil

4. H₂O

Vapour phase refining can be carried out in case of 

1. Ni

2. Zr

3. Ti

4. All of these

The extraction of gold and silver involves leaching with CN^- ion. Silver is later recovered by:

1. Liquation

2. Distillation

3. Zone refining

4. Displacement with Zn

Aluminium is extracted from alumina (Al₂O₃) by electrolysis of a molten mixture of

1. Al₂O₃ + HF + NaAlF₄

2. Al₂O₃ + CaF₂ + NaAlF₄

3. Al₂O₃ + Na₃AlF₆ + CaF₂

4. Al₂O₃ + KF +Na₃AlF₆

Which one of the following is a mineral of iron?
(a) Malachite
(b) Cassiterite
(c) Pyrolusite
(d) Magnetite