Zn+2 forms soluble complex with excess KCN but does not react with excess KI Pb+2 is soluble in excess Kl but insoluble in excess KCNAg+ is soluble in excess KCN but insoluble in excess KI Hg2+2 gives ppt of Hg when reacts with KI as well as well as excess KCN Hg22++2l−⟶Hg2I2↓ Hg2I2↓+2l−⟶[Hgl4]2−+Hg↓ Hg22++2CN−⟶Hg