Question

How are metals like sodium, potassium, and calcium obtained? Give equations.

Answer 1

Metals are produced through the electrolytic reduction of fused metallic salts (halides or oxides) using an inert electrode. The cathode is usually made of iron and the anode is of graphite.

Sodium
Electrolyte:	Fused sodium chloride
Reaction:	\[\ce{NaCl <=> Na^+ + Cl^-}\]
Reaction at cathode:	\[\ce{Na^+ + e^- -> Na}\]
Reaction at anode:	\[\ce{Cl^- - e^- -> Cl}\]
	\[\ce{Cl + Cl -> Cl2}\]

 

Potassium
Electrolyte:	Fused potassium bromide
Reaction:	\[\ce{KBr <=> K^+ + Br^-}\]
Reaction at cathode:	\[\ce{K^+ + e^- -> K}\]
Reaction at anode:	\[\ce{Br^- - e^- -> Br}\]
	\[\ce{Br + Br -> Br2}\]

 

Calcium
Electrolyte:	Fused calcium chloride
Reaction:	\[\ce{CaCl2<=> Ca^{2+} + 2Cl^-}\]
Reaction at cathode:	\[\ce{Ca^{2+} + 2e^- -> Ca}\]
Reaction at anode:	\[\ce{Cl^- - e^- -> Cl}\]
	\[\ce{Cl + Cl -> Cl2}\]