Question

Among the following reactions, which one occurs at the cathode in the Hall–Héroult process?

• A. $A{l}^{3+}+3e^{-}\to Al$
• B. $2O{}^{2-}\to O_2+4e^{-}$
• C. $3C+1.5O_2\to 3CO$
• D. $2F^{-}\to F_2+2e^{-}$

Answer 1

The correct option is A $A{l}^{3+}+3e^{-}\to Al$

The following reactions occur at the cathode and anode in the Hall–Héroult process.
Remember: Cathode is where reduction happens, anode is where oxidation happens.
At cathode:
$A{l}^{3+}+3e^{-}\to Al$

At anode:
1. $2O{}^{2-}\to O_2+4e^{-}$
2. $3C+1.5O_2\to 3CO$