Vapour Phase Refining

Q.

Write the principle of vapour phase refining.

Q.

Give two requirements for vapour phase refining.

Q.

Van Arkel method is used for

1. Concentration

2. Leaching

3. Roasting

4. Refining

Q. The metal for which, its property of formation of volatile complex is taken into account for its extraction is:

1. Cobalt
2. Nickel
3. Vanadium
4. Iron

Q. In the preparation of alum from alum shale $FeS{O}_4$ is removed by :

1. Distillation
2. Fractional Distillation
3. Crystalization
4. Fractional Crystalization

Q. Write the principle behind the following methods of refining:
(i) Hydraulic washing
(ii) Vapour-phase refining

Q. The metal for which, its property of formation of volatile complex is taken into account for its extraction is:

1. Cobalt
2. Nickel
3. Vanadium
4. Iron

Q. What is the refining method used for the refining of Lead?

Q. Give two requirements for vapour phase refining.

Q. Which statements are correct in terms of chemical kinetic stuides?

1. The quenching of a reaction can be made by cooling the reaction mixture.
2. The quenching of a reaction can be made by diluting the reaction mixture.
3. The reaction is supposed to be completed if it is kept for long time or strongly heated.
4. None of the above

Q.

For each of the substance listed below, describe the role played in the extraction of aluminium.

Cryolite

Q. Which of the following are main requirements for vapour phase refining?
(i) Metal should form a volatile compound with the reagent.
(ii) The volatile compound should be easily decomposable to give back pure metal.
(iii) Metal should be very reactive and form a stable compound with the reagent.

1. (i) and (ii)
2. (ii) and (iii)
3. (i), (ii) and (iii)
4. (i) and (iii)

Q. Nickel is purified by thermal decomposition of its:

1. Azide
2. Hydride
3. Chloride
4. Carbonyl

Q.

You are given the description of a process called “Vapour phase refining” Vapour Phase Refining: This involves converting the crude metal into a volatile intermediate. This intermediate should also decompose on heating at a reasonable temperature. Which of the following could be categorized under ‘Vapour phase refining’?

1. Baeyer’s process

2. Mond’s Process

3. Mac-Arthur Forrest (Cyanide) process

4. Van Arkel de-Boer process

Q. Why NaCN is used during the extraction of of Au or Ag from native ore(in leaching), ?.?