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
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 |