Q. No.Extraction of gold and silver involves leaching with CN- ion. Silver is later recovered by:
1. Distillation
2. Zone refining
3. Displacement with Zn
4. Liquation
Considering Ellingham diagram, which of the following metals can be used to reduce alumina?
1. Fe
2. Zn
3. Mg
4. Cu
Match items of Column I with the items of Column II and assign the correct code.
| Column I | Column II |
| A) Cyanide process | 1) Ultra pure Ge |
| B) Froth floatation Process |
2) Dressing of ZnS |
| C) Electrolytic | 3) Extraction of Al Reduction |
| D) Zone refining | 4) Extracting of Au |
| A | B | C | D | |
| 1. | 2 | 3 | 1 | 4 |
| 2. | 1 | 2 | 3 | 4 |
| 3. | 3 | 4 | 2 | 1 |
| 4. | 4 | 2 | 3 | 1 |
In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with?
1. Iron(II) sulphide
2. Carbon monoxide
3. Copper(I) sulphide
4. Sulphur dioxide
"Metals are usually not found as nitrates in their ores". Out of the following two (I and II) reasons which is/are true for the above observation?
| I: | Metal nitrates are highly unstable. |
| II: | Metal nitrates are highly soluble in water. |
2. I and II are False
3. I is False but II is True
4. I is True but II is False
Roasting of sulphides gives the gas X as a by-product. This is a colourless gas with a choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic and acts as an oxidizing agent and its acid has never been isolated. The gas X is:
1. SO2
2. CO2
3. SO3
4. H2S
Which one of the following is a mineral of iron?
1. Malachite
2. Cassiterite
3. Pyrolusite
4. Magnetite
Which of the following elements is present as an impurity to the maximum extent in the pig Iron?
1. Carbon
2. Silicon
3. Phosphorus
4. Manganese
| 1. | Carbon and hydrogen act as suitable reducing agents for metal sulphides |
| 2. | The \(\Delta_f G^0\) of the sulphide is greater than those for \(C S_2\) and \(\mathrm{H}_2 \mathrm{~S}\) |
| 3. | The \(\Delta_f G^0\) is negative for roasting of sulphur ore to oxide. |
| 4. | Roasting of the sulphide to the oxide is thermodynamically feasible |
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