Carbon cannot reduce the oxides of sodium, magnesium and aluminium to their respective metals. Why? Where are these metals placed in the reactivity series? How are these metals obtained from their ores? Take an example to explain the process of extraction along with chemical equations.

Explanation

Metals which are placed high in the reactivity series such as sodium, calcium, magnesium, aluminium etc. are very reactive. These metals have high affinity for oxygen than carbon. Therefore, these metals cannot be obtained by reduction with carbon
For such metals, electrolytic reduction process is used for obtaining metal .
Electrolytic reduction of aluminium : Molten aluminium oxide is electrolysed to produce pure aluminium at the cathode while oxygen gas is produced at the anode
`A l^(3+) + 3e^(-)` to Al` (aluminum metal at the (-) cathode )
`2O^(2-) - 4e^(-) to O_(2)` (oxygen gas at the (+) anode )

Electrolytic cell for the extraction of aluminium