Which metal is extracted from bauxite?

Step 1: Analyze the question The question asks which metal is obtained from the ore called bauxite.

Step 2: Explain the concept Bauxite is the main ore of aluminium. It is mainly hydrated aluminium oxide, Al₂O₃·2H₂O. Nigeria has some bauxite deposits, but most of the world's supply comes from countries such as Australia and Guinea.

Step 3: Show the process Aluminium is extracted in two main stages:

1. Purification (Bayer process): Bauxite is dissolved in hot concentrated sodium hydroxide. Aluminium oxide dissolves, and impurities such as iron(III) oxide do not. The solution is filtered, then the aluminium hydroxide is precipitated and heated to give pure alumina (Al₂O₃).

2. Electrolysis (Hall-Héroult process): The pure alumina is dissolved in molten cryolite (Na₃AlF₆), which lowers the melting point from about 2000°C to about 900°C. The mixture is electrolysed using carbon electrodes. • Cathode: Al³⁺ + 3e⁻ → Al • Anode: 2O²⁻ → O₂ + 4e⁻

Step 4: Check the other options

• Calcium comes from limestone or chalk, or by electrolysis of molten calcium chloride.
• Copper comes from copper pyrites or malachite.
• Magnesium comes from magnesite, dolomite, or sea water.
• Tin comes from cassiterite (SnO₂), which is mined on the Jos Plateau in Nigeria.

Answer: The metal extracted from bauxite is aluminium, which is option A.

Tip: Match each ore to its metal:

• Bauxite → Aluminium
• Cassiterite → Tin
• Haematite → Iron
• Galena → Lead
• Zinc blende → Zinc