Question

Write short notes on Electrometallurgy with example.

Answer 1

Electrometallurgy:

Oxides, hydrides and chlorides of electropoitive metals like Na, K, Mg, Al,Ca are extracted by the electrolysis of their fused salts and pure metal is obtained on cathode. This is known as electrolytic reduction. It is based on electrochemical principle.
According to equation ∆G° = – nFE°, for a system (cell), difference of electrode potential for redox couple is positive, value of resultant ∆G° becomes negative by which more reactive metal goes in to solution and less reaceive metal moves out of the solution, therefore it is released at cathode.
For example:
NaCl \(\overset{Electrolytic}{\underset{Reduction}{\longrightarrow}}\) Na⁺ + Cl^–
Fused form
At cathode: Na⁺ + e^– → Na
At anode: Cl^– → \(\frac { 1 }{ 2 } \)Cl₂ + e^–