Key Points
Key Points: Aluminium
- Symbol and Properties: Aluminium (Al) is a silvery white metal with a specific gravity of 2.2 and a relative atomic mass of 27.
- Atomic Details: It has an atomic number of 13, valency of 3, and an electronic configuration of 2, 8, 3.
- Periodic Table Position: Aluminium is located in Period 3, Group IIIA (13) of the Periodic Table.
- Abundance and Reactivity: It is the most abundant metal in the Earth's crust and is highly reactive, hence not found free in nature.
- Discovery: Aluminium was discovered by Hans Christian Ørsted in 1825.
Key Points: Extraction of Aluminium
- Extraction: Aluminium is extracted from bauxite using Bayer’s process and electrolytic reduction.
- Purification: Bauxite is purified with NaOH, forming alumina (Al₂O₃) after filtering and heating.
- Electrolysis: Alumina is dissolved in cryolite and reduced by electrolysis to get aluminium metal.
Key Points: Electrolytic Reduction of Refused Alumina
- Cell Setup: Iron tank with carbon lining (cathode) and graphite rods (anode).
- Electrolyte: Molten mix of alumina, cryolite, and fluorspar at 950°C.
- Main Reactions: Aluminium forms at the cathode; oxygen at the anode forms CO and CO₂.
- Cryolite & Fluorspar: Lower melting point and improved conductivity.
- Powdered Coke: Prevents heat loss and protects the anode.
