Zone refining is based on the principle that-
1. | Impurities of low-boiling metals can be separated by distillation. |
2. | Impurities are more soluble in molten metal than in solid metal. |
3. | Different components of a mixture are differently adsorbed on an adsorbent. |
4. | Vapours of volatile compounds can be decomposed in pure metal. |
Which of the following statement is correct?
1. | Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast. |
2. | In the extraction of silver, silver is extracted as a cationic complex. |
3. | Nickel is purified by zone refining. |
4. | Zr, and Ti are purified by the van Arkel method. |
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)
From the following, the correct statements about the role of substances added in the froth flotation process are:
a. | Collectors enhance the non-wettability of the mineral particles. |
b. | Collectors enhance the wettability of gangue particles. |
c. | By using depressants in the process, two sulphide ores can be separated. |
d. | Froth stabilisers decrease the wettability of gangue. |
1. a and b
2. b and c
3. c and d
4. a and c
The following method of purification, where metal is converted to its volatile compound that gives pure metal is upon the decomposition :
a. Heating with a stream of carbon monoxide.
b. Heating with iodine.
c. Liquation
d. Distillation
Choose the correct option :
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)
Match the items in Column I with the items in Column II and assign the correct code.
Column I | Column II |
A. Coloured Bands | 1. Zone refining |
B. Impure metal to volatile complex | 2. Fractional distillation |
C. Purification of Ge and Si | 3. Mond’s process |
D. Purification of mercury | 4. Chromatography |
5. Liquation |
Codes
A | B | C | D | |
1. | 1 | 2 | 3 | 4 |
2. | 4 | 3 | 1 | 2 |
3. | 3 | 4 | 2 | 1 |
4. | 5 | 4 | 3 | 2 |
Match the items in Column I with the items in Column II, and assign the correct code.
Column I | Column II |
A. Cyanide process | 1. Ultrapure Ge |
B. Froth flotation process | 2. Dressing of ZnS |
C. Electrolytic reduction | 3. Extraction of Al |
D. Zone refining | 4. Extraction of Au |
5. Purification of Ni |
Codes
A | B | C | D | |
1. | 4 | 2 | 3 | 1 |
2. | 2 | 3 | 1 | 5 |
3. | 1 | 2 | 3 | 4 |
4. | 3 | 4 | 5 | 1 |
Assertion (A): | Nickel can be purified by Mond’s process. |
Reason (R): | It is a volatile compound that decomposes at 460 K to give pure Ni. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Assertion (A): | Zirconium can be purified by the van Arkel method. |
Reason (R): | ZrI4 is volatile and decomposes at 1800 K. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
Assertion (A): | The zone refining method is very useful for producing semiconductors. |
Reason (R): | Semiconductors are of high purity. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |