A colourless aqueous solution contain nitrates of two metal, when it is added to an aqueous solution of NaCl, a white precipitate ws formed. This precipitate was found to be partially soluble in hot water to give a residue P and a solution Q. The residue P was solublein aq. in NH3 and also in excess sodium thiosulfate. The hot solution Q gave a yellow precipitate with KI. The metals X and Y, respectively, are:
(2) AgCl(s)+2NH3→[Ag(NH3)2]+Cl−(P)(soluble complex)
(3) AgCl+2Na2S2O3→Na3[Ag(S2O3)]+NaClResidue P(Excess)(Soluble complex)
(4)
Pb(NO3)2+2NaCl→PbCl2↓+2NaNO3(y)white ppt (Q)
(5) PbCl2+2KI→PbI2+2KCl(hot solution)yellow pptQ