Question

Which of the following processes is used for the manufacture of calcium?

• A. Reduction of $CaO$ with carbon
• B. Reduction of $CaO$ with hydrogen
• C. Electrolysis of a mixture of anhydrous ${CaCl}_2$ and $KCl$
• D. Electrolysis of molten ${Ca\left(OH\right)}_2$

Answer 1

Answer: (C)

Electrolysis of a mixture of anhydrous ${CaCl}_2$ and $KCl$

Calcium is obtained by electrolysis of a fused mass of ${CaCl}_2$ and $KCl$ at about ${700}^{\circ }C$ in an electrolytic cell made of graphite anode and iron cathode.
${CaCl}_2\rightleftharpoons {Ca}^{2+}+2{Cl}^{-}$
At anode
$2{Cl}^{-}⟶{Cl}_2+2e^{-}$
At cathode
${Ca}^{2+}+2e^{-}⟶Ca$