Question

The oxides of metals like an Na, Mg, Ca cannot be reduced by carbon

Answer 1

Carbon is less reactive than metals like Sodium, Magnesium and Calcium and cannot reduce them from their respective ores.

Hence they are reduced by electrolytic refining.

Answer 2

Answer:

This is because sodium and magnesium are more reactive than carbon. This means that carbon cannot reduce the oxides of these metals. The two metals are above carbon in the reactivity series and thus have a high affinity to oxygen than carbon does and thus cannot be reduced by it.