Final answer:
The CAC-A process in smelting uses a source of carbon, such as coke, as a chemical reducing agent to melt the base metal from its ore. In iron extraction using a blast furnace, coke reduces iron oxide to molten iron. In the Hall-Heroult process for aluminum production, coke is used at the anode during the electrolysis of a molten mixture containing aluminum oxide.
Step-by-step explanation:
The CAC-A process, which refers to the smelting process in metallurgy, uses heat and a chemical reducing agent to melt the base metal from its ore. The reducing agent is typically a source of carbon, such as coke or charcoal. For instance, in the extraction of iron from iron ore using a blast furnace, coke serves as the reducing agent and reacts with the iron ore (in the form of iron(III) oxide) to produce molten iron and carbon dioxide, as represented by the chemical equation: 2Fe2O3 + 3C → 4Fe + 3CO2.
In the Hall-Heroult process for producing aluminum, coke serves as the carbon anode, and molten aluminum is produced at the cathode during the electrolysis of a molten mixture of aluminum oxide and cryolite. The chemical reaction is: 2 Al2O3 (l) + 3 C(s) → 4 Al(l) + 3 CO2 (g).
Another application of heat to melt metal is found in the use of an oxyacetylene torch, which generates heat through the combustion of acetylene in oxygen. This exothermic reaction is capable of melting the metal for various applications such as cutting or welding.