In the context of the Hall- Heroult process for the extraction of $Al$ which of the following statement is false ?

Question

$\begin{array}{1 1} Al_2O_3 \text{is mixed with $CaF_2$ which lower the melting point of the mixture and brings conductivity } \\ Al^{3+} \text{is reduced at the cathode to form Al} \\ Na_3AlF_6 \text{serves as the electrolyte } \\ CO \;and\;CO_2 \text{are produced in this process } \end{array}$