1. Analysis of a Mixture of Cations
ANALYSIS OF THE
SILVER GROUP CATIONS
Ag Hg Pb2+
Analysis of a Mixture of Cations

2. ANALYSIS OF THE SILVER GROUP CATIONS
CHEMISTRY OF THE SILVER GROUP CATIONS
Silver(I), lead(II), and mercury(I) are grouped together in qualitative analysis schemes because they are the only common metal cations that form insoluble precipitates with chloride ion. For example

3. ANALYSIS OF THE SILVER GROUP CATIONS
This means that, in a mixture of metal cations, these three metal Ions can be separated from all others by Precipitating them. Their insoluble chlorides, usually with 6 M HCl.

4. ANALYSIS OF THE SILVER GROUP CATIONS

5. ANALYSIS OF THE SILVER GROUP CATIONS

6. ANALYSIS OF THE SILVER GROUP CATIONS
The first step in separating the three chlorides is to treat the solid mixture with hot water to selectively dissolve PbCl2and to leave AgCl and HgCl2 as a solid mixture.
The Pb2+ ion and the chromate ion, CrO42-, combine to form the bright yellow, insoluble solid lead(II) chromate, PbCrO4

7. ANALYSIS OF THE SILVER GROUP CATIONS

8. ANALYSIS OF THE SILVER GROUP CATIONS
We take advantage of the tendency of transition metal ions such as Ag+ to form water-soluble complex ions with ammonia, NH3. Here the ammonia uses the lone pair of electrons of the N atom to form a bond with the Ag+ ion.

9. ANALYSIS OF THE SILVER GROUP CATIONS
Mercury(I) chloride can undergo what is known as a disproportionation reaction. That is, the mercury(I) ion is both oxidized [to mercury(II), Hg2+] and reduced (to metallic mercury).

10. ANALYSIS OF THE SILVER GROUP CATIONS

11. ANALYSIS OF THE SILVER GROUP CATIONS

12. ANALYSIS OF THE SILVER GROUP CATIONS

13. ANALYSIS OF THE SILVER GROUP CATIONS
Tools of the test
1- Test tube

14. ANALYSIS OF THE SILVER GROUP CATIONS

15. ANALYSIS OF THE SILVER GROUP CATIONS
2- Dropper

16. ANALYSIS OF THE SILVER GROUP CATIONS
3- Washing bottle

17. ANALYSIS OF THE SILVER GROUP CATIONS
4- Centrifuge

18. ANALYSIS OF THE SILVER GROUP CATIONS
5- Water path