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

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

(1) copper (I) sulphide (Cu₂S)

(2) sulphur dioxide (SO₂)

(3) iron sulphide (FeS)

(4) carbon monoxide (CO)