Concept:Highly reactive alkali metals cannot be extracted from aqueous solutions via electrolysis because water would be reduced instead of the metal ions.
Solution:- To extract pure metallic Sodium, industrial chemists use a specialized electrolytic apparatus known as the Downs cell.
- In the Downs cell, molten Sodium Chloride (\( NaCl \), mixed with \( CaCl_2 \) to lower the melting point) is electrolyzed.
- Sodium ions (\( Na^+ \)) are reduced at the iron cathode to form liquid metallic Sodium, while Chloride ions (\( Cl^- \)) are oxidized at the carbon anode to form Chlorine gas.
Why other options are incorrect:Magnesium is typically extracted using a Dow cell (similar, but specifically for \( MgCl_2 \)). Aluminum uses the Hall-Héroult process. Iron is extracted via pyrometallurgy in a blast furnace.
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