Zone Refining

Q.

You are an alchemist who is trying to remove hard lead impurity from Crude silver. You can only use thermal refining by using a blast of air. What would you use?

1. Linz-Donawitz process

2. Van Arkel-de Boer Refining

3. Mond’s process

4. Cupellation

Q.

You are an alchemist who is trying to remove hard lead impurity from Crude silver. You can only use thermal refining by using a blast of air. What would you use?

1. Van Arkel-de Boer Refining

2. Mond’s process

3. Cupellation

4. Linz-Donawitz process

Q. Zone refining is based on the principle that the impurities are more soluble in the melt than in the solid metal.

1. True
2. False

Q. When an impurity in a metal has a greater affinity towards oxygen and is more easily oxidized than the metal itself, then the metal is refined by:

1. Cupellation
2. Zone refining
3. Poling
4. Electrolytic process

Q. Zone refining method often yields 80-85% of pure metal

1. True
2. False

Q. Zone refining is used for the purification of

1. $Ge$
2. $Si$
3. $Ga$
4. $Se$

Q.

Explain:

Zone refining

Column chromatography .

Q.

How are metals used as semiconductors refined? What is the principle of the method used like germanium, silicon etc?

Q.

Match the items of Column I with the items of Column II and assign the correct code.
$\begin{array}{cc}ColumnI& ColumnII\\ A.Colouredbands& 1.Zonerefining\\ B.Impuremetaltovolatilecomplex& 2.Fractionaldistillation\\ C.PurificationofGeandSi& 3.Mon{d}^{\prime }sprocess\\ D.Purificationofmercury& 4.Chromatography\\ & 5.Liquation\end{array}$
Codes
A B C D A B C D
(a) 1 2 4 5 (b) 4 3 1 2
(c) 3 4 2 1 (d) 5 4 3 2

Q. Zone refining is a method to obtain:

1. ultra pure boron
2. ultra pure lead
3. ultra pure silicon
4. all