Question

During electrolytic reduction of molten Alumina, Aluminium metal is obtained at

• A. Carbon anode
• B. Carbon cathode
• C. Aluminium anode
• D. Aluminium cathode

Answer 1

The correct option is B

Carbon cathode

The explanation for the correct answer:

Option B: Carbon cathode

• Electrolysis of the Alumina/cryolite solution gives Aluminium at the cathode and Oxygen at the anode.
• The electrode reaction at the cathode:

$$\begin{gathered} {\mathrm{Al}}^{3+}+3{\mathrm{e}}^{-}\to \mathrm{Al} \\ \mathrm{Aluminium} \\ \mathrm{atom} \end{gathered}$$

• The electrode reaction at the anode:

$$\begin{gathered} 2{\mathrm{O}}_2^{-}\to {\mathrm{O}}_2+4{\mathrm{e}}^{-} \\ \mathrm{Oxygen} \\ \mathrm{gas} \end{gathered}$$

• As in electrolysis of the Alumina/Cryolite solution gives Aluminium at the cathode which is made of Carbon and Oxygen at the Anode.

Hence, Option B is correct. During electrolytic reduction of molten Alumina, Aluminium metal is obtained at Carbon cathode.