Metallurgy

In the cyanide extraction process of silver, silver ore is treated with sodium cyanide solution in the presence of oxygen, which oxidizes the silver to form soluble complexes. The reducing agent used in this process is zinc dust (Zn), which reduces the silver complex back to metallic silver. The process is commonly known as the MacArthur-Forrest process.
Thus, the correct oxidizing and reducing agents are O and Zn dust, respectively.

The correct option is (A): A-IV, B-II. C-III, D-I

The correct option is (C) : A-II, B-III, C-IV, D-I

The correct option is (C) : A-II, B-IV, C-III, D-I

Let's go through each option and match them with the corresponding items in List II.
- (A) Electrolytic reduction: This process involves the reduction of metal ions to metal using electricity. This is commonly used in the extraction of aluminium (III) from its oxide (Al O ) using the Hall-Héroult process. So, Electrolytic reduction is related to Aluminium (III).
- (B) Bessemerization: This process is used for converting pig iron to steel by blowing oxygen through it, and it is closely related to the production of Iron (I).
Therefore, Bessemerization is related to Iron (I).
- (C) Smelting: Smelting is a process of extracting metals from ores using heat. It is used to obtain metals like Zinc (II) from their ores (e.g., zinc oxide). So, Smelting is associated with Zinc (II).
- (D) Reduction from oxide: This process is used for extracting metals from their oxides using a reducing agent (usually carbon). Copper (IV) is commonly extracted from its oxide using carbon. Hence, Reduction from oxide is related to Copper (IV).
Thus, the correct answer is (A)-(III), (B)-(I), (C)-(II), (D)-(IV).