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

An ore on being heated in air forms sulphurous anhydride. Write the process used for the concentration of this ore.

Define roasting. Name an ore on which roasting is done. Give balanced equation.

Define calcination. Give an example and equation for calcination.

How are the metals like sodium, potassium and calcium obtained? Give equations.

Give equations for the reduction of

Copper oxide

Give equation for the reduction of

Iron (III) oxide

Give equations for the reduction of

Lead (II) oxide

Give equations for the reduction of

Zinc oxide