Lead chloride is almost three times more soluble in hot water than cold. One may use this as a basis for separating it from silver chloride. The presence of lead is then confirmed by precipitation of yellow lead chromate. Centrifuge while hot, decant, and save both the solution and the solid. Add 2-3 drops of 1 M K 2 CrO 4 to the solution.
Silver forms a soluble complex ion with aqueous ammonia.
The solid should dissolve, but if any precipitate remains, centrifuge and proceed using only the centrifugate. Add 6 M HNO 3 to the solution until the solution is acidified, using pH indicator paper to test for acidification. The Cl - needed for precipitation will be present from the prior dissolution of AgCl. To perform this test on a known solution containing silver ions, add HCl to the solution to observe the AgCl precipitation. The Group II ions are separated from those in Group III by adding hydrogen sulfide to the mixture in acidic solution.