Match List I with List II

Choose the correct answer from the options given below:

A-IV, B-II, C-III, D-I

The correct answer is option 1. A-IV, B-II, C-III, D-I.

Here is an explanation for each of the given processes and its associated metal or substance:

A. Zone Refining: This is a purification technique used for semiconductors like germanium and silicon. In this process, a rod of impure semiconductor material is slowly passed through a high-frequency induction coil, which creates a molten zone. As the zone moves along the rod, impurities are selectively partitioned into the molten zone, resulting in a purer region behind the moving zone. This method is particularly effective for removing impurities from semiconductors, ensuring high-quality materials for electronic devices.

B. Blast Furnace: The blast furnace is a large, vertical furnace used for smelting iron from its ores, primarily hematite \((Fe_2O_3)\) and magnetite \((Fe_3O_4)\). In the blast furnace, iron ore, coke (carbon), and limestone are introduced at the top, and hot air is blown into the bottom. The intense heat generated by the combustion of coke reduces the iron oxides in the ore to molten iron, which collects at the bottom of the furnace. The limestone acts as a flux, combining with impurities to form slag, which floats on top of the molten iron and is removed. The molten iron, known as pig iron, is then cast into molds for further processing.

C. Froth Flotation Process: This process is used for the concentration of sulfide ores, including copper, lead, and zinc ores. In froth flotation, finely ground ore is mixed with water and chemicals, including frothing agents and collectors. Air is then bubbled through the mixture, causing the valuable minerals to attach to the air bubbles and rise to the surface as a froth. The froth, containing the concentrated mineral particles, is skimmed off and further processed to extract the desired metal.

D. Hall-Héroult Process: This is the primary method for the production of aluminum from bauxite ore. In the Hall-Héroult process, alumina \((Al_2O_3)\) is dissolved in molten cryolite \((Na_3AlF_6)\) at high temperatures. An electric current is then passed through the molten mixture, causing the aluminum ions to migrate to the cathode, where they are reduced to molten aluminum metal. Oxygen ions migrate to the anode, where they react with carbon to form carbon dioxide. The molten aluminum is then collected and cast into ingots for further processing.

These processes play critical roles in the extraction, purification, and production of various metals and substances essential for industrial and technological applications.