The correct answer is option 2. A-IV, B-I, C-II, D-III.
Let us go into detail about each process and its corresponding activity:
A. Zone Refining (IV - Ultrapure Ge):
Zone refining is a method used to purify semiconductors, especially germanium (Ge) and silicon (Si). In this process, a rod of the impure semiconductor is slowly passed through a high-frequency induction coil. This creates a molten zone that moves along the rod. As the molten zone progresses, impurities are selectively incorporated into the liquid phase, leaving behind a more purified solid portion. This process is repeated to obtain ultrapure germanium.
B. Froth Floatation Process (I - Dressing of ZnS):
Froth flotation is a method used for the concentration of ores. In the dressing of zinc sulfide (ZnS) ore, the ore is crushed and then mixed with water and suitable reagents. Air is bubbled through the mixture, creating a froth that carries the ore particles to the surface, where they can be collected. This is an effective method for separating minerals based on their hydrophobic and hydrophilic properties.
C. Cyanide Process (II - Extraction of Au):
The cyanide process is used for the extraction of gold (Au) from its ore. In this process, finely ground gold ore is treated with a dilute solution of sodium cyanide. The gold dissolves forming a soluble complex. The gold is then precipitated from the solution by adding zinc dust. This method is widely used in the mining industry for extracting gold from low-grade ores.
D. Electrolytic Reduction (III - Extraction of Al):
The electrolytic reduction process is used for the extraction of aluminum (Al) from its ore, bauxite. In this process, aluminum oxide (alumina) is dissolved in molten cryolite and subjected to electrolysis. The aluminum ions are reduced at the cathode, forming molten aluminum that is collected at the bottom of the electrolytic cell. This method is energy-intensive but crucial for the production of aluminum.
So, the correct match is 2. A-IV, B-I, C-II, D-III | 
