(a) Name an ore of zinc

(b) Which process is applied to concentrate it?

(c) How is concentrated ore changed to oxide?

(a) Some metallic oxides can be reduced by hydrogen, carbon, carbon monoxide and some cannot. Explain.

(b) Write balanced equation for the reduction of copper (II) oxide by hydrogen.

State why aluminium is extracted from it's 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.