In the extraction of aluminium by electrolytic process, cryolite is added to reduce the melting point of the mixture. The use of cryolite reduces some of the energy cost involved in extracting aluminium. Reactions involved in the electrolysis are given below Al2O3⇌2Al+3+3O−2 Na3AlF6⇌3Na++Al+3+6F CaF2⇌Ca+2+2F At cathode Al3++3e−⟶Al (reduction) At anode C+O2−⟶CO+2e−(oxidation) C+2O2−⟶CO2+4e−