Question

State why aluminium is extracted from its oxide by electrolysis while copper, lead, iron by reducing agents and mercury and silver by thermal decomposition.

Answer 1

Aluminium has a great affinity for oxygen and so cannot be reduced by carbon or carbon monoxide. So, it is extracted from its oxide by electrolysis.
Metals like copper, lead, and iron are placed in the middle of the activity series and are moderately reactive, and carbon, CO and hydrogen can reduce their oxides. Mercury and silver are less reactive and are placed lower in the reactivity series. The oxides of these metals are reduced to metals by heating their oxides.