Lead has been placed in the group I and II because
Answer»
it shows the valency of one and two it forms INSOLUBLE `PbCl_(2)` it forms lead sulphide it is partially soluble in water
Solution :`PbCl_(2)` is partially soluble in water and dissolves completely only in hot water. So , part of it goes to group II, Where it is precipitated as PbS.