Question

Give the reason for the following.
Highly reactive metal cannot be obtained from their oxides by heating them with carbon.

Answer 1

Hint: We must know which are the highly reactive metals are. The highly reactive metals are those which lie at the top in the reactivity series. Metals like potassium, sodium, calcium and aluminium are known as highly reactive metals.

Complete answer:
The highly reactive metals are potassium, sodium, calcium and aluminium.
These highly reactive metals are generally present in the form of their oxides. The oxides of these metals are very stable in nature.
The conversion of metal oxides to the metals is generally done while extraction of the metals from the ores.
These metals have more affinity towards oxygen than carbon and thus, carbon is unable to remove the oxygen from the oxides of these metals and convert the metals into free states.
The metals that are less reactive than carbon can be extracted from their oxides by reduction of their oxides with carbon. Iron can be obtained by reduction with carbon.
Thus, the oxides of highly reactive metals cannot be reduced by carbon. Thus, highly reactive metal cannot be obtained from their oxides by heating them with carbon.

Note: The highly reactive metals like potassium, sodium, calcium and aluminium are more reactive than carbon. Thus, they cannot be extracted from their oxides by carbon. These highly reactive metals are extracted from their ores by electrolytic reduction. In the process of electrolytic reduction, metals are extracted from their oxides or chlorides in molten state. In the process, metal particles get collected at the cathode and the oxygen or chlorine get collected at the anode.