Q.The metal extracted by Hall-Heroult process is :

The Hall-Heroult process electrolyses alumina dissolved in molten cryolite to deposit molten aluminium metal at the cathode.

In the Hall-Heroult process, purified alumina ($Al_2O_3$, obtained from bauxite via the Bayer process) is dissolved in molten cryolite ($Na_3AlF_6$) along with a little fluorspar ($CaF_2$) to lower the melting point and increase conductivity. On electrolysis in a carbon-lined steel cell (acting as cathode) with carbon anodes, $Al^{3+}$ ions are reduced and molten aluminium metal collects at the bottom (cathode), while oxygen liberated at the anode burns away the carbon anodes as $CO_2$. Cu is extracted by electrolytic refining/smelting of copper ores, Zn mainl …