Electrolysis and Metal Extraction

Electrolysis is a process that uses an electric current to drive a non-spontaneous chemical reaction. It is commonly used for metal extraction from their ores. During electrolysis, the metal ions present in the compound are reduced at the cathode (negative electrode), while oxidation occurs at the anode (positive electrode).

Aluminium Extraction

Aluminium is extracted through the process of electrolysis. It is obtained from its ore, bauxite, which is primarily composed of aluminium oxide (Al2O3). The extraction of aluminium involves the following steps:

1. Extraction of Alumina: Bauxite ore is first purified to obtain alumina (Al2O3) through the Bayer's process. In this process, bauxite is dissolved in sodium hydroxide (NaOH) solution, and impurities are removed. The resulting solution is then cooled and filtered to obtain pure alumina.

2. Electrolysis of Alumina: The alumina obtained in the previous step is mixed with cryolite (Na3AlF6) and heated to form a molten electrolyte. This mixture reduces the melting point of alumina, making the electrolysis process more efficient. The molten electrolyte is then electrolyzed using carbon electrodes.

At the cathode: Aluminium ions (Al3+) are reduced and deposited as molten aluminium metal (Al).

At the anode: Oxygen ions (O2-) are oxidized to form oxygen gas (O2).

Since aluminium extraction involves the use of electrolysis, it is the correct answer for the given question.

Other Metals Extraction

- Zinc (Zn): Zinc is not extracted by electrolysis. It is primarily obtained from its ore, zinc blende (ZnS), through a process called roasting and smelting.

- Iron (Fe): Iron is extracted from its ore, hematite (Fe2O3), through a process called reduction with carbon. Electrolysis is not involved in the extraction of iron.

- Copper (Cu): Copper is primarily obtained from its ore, copper pyrite (CuFeS2), through a process called smelting. Electrolysis is not used in the extraction of copper.

Therefore, among the given options, aluminium (Al) is the only metal that is extracted using electrolysis.