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

Options

A. CO and `CO_2` are produced in this process
B. `Al_2O_3` is mixed with `CaF_2` which lowers the melting point of the mixture and brings conductivity
C. `Al^(3+)` is reduced at the cathode to form Al
D. Na3AlF6 serves as the electrolyte

Answer

D

Explanation

Silver is extracted form argentite ore by the process of leaching . In the first step, argentite ore reacts with KCN or NaCN to form a co - ordination compound . In the second step , the co - ordination compound reacts with zinc, to produce silver metal.
`Ag_2S+KCN+underset("Oxidant")(O_2)rarrK[Ag(CN)_2]+K_2S_2O_3`
`2K[Ag(CN)_2]+underset("Reluctant")(Zn)rarrK_2[Zn(CN)_4)+2Agdarr`
Thus, `O_2` and Zn are oxidant (oxidising agent) and reluctant (reducing agent ) respectively.