Qualitative analysis of group 4 cations

1,263 views
1,004 views

Published on

The Group IV cations are Ba2+, Sr2+, Ca2+.
These metals form chlorides, sulfides and hydroxides that are soluble under that prevail in the precipitations of Group I, II, and III.

Published in: Science, Technology, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
1,263
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
19
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Qualitative analysis of group 4 cations

  1. 1. Jessa S. Ariño BSE-4B Central Bicol State University of Agriculture ANALYSIS OF GROUP IV CATIONS
  2. 2. Group Separations in Qualitative Analysis
  3. 3. Group Separations in Qualitative Analysis
  4. 4. Precipitation of Group 4-Cations • The Group IV cations are Ba2+, Sr2+, Ca2+. • These metals form chlorides, sulfides and hydroxides that are soluble under that prevail in the precipitations of Group I, II, and III.
  5. 5. • The carbonates of barium, strontium, and calcium precipitate in aqueous ammonia solutions containing ammonium carbonate. • These conditions give a carbonate concentration high enough to precipitate BaCO3, SrCO3, and CaCO3 but not MgCO3.
  6. 6. • To bring the solution to the required ammonium concentration, the centrifugate from Group III separation, which contains ammonium salts, is first evaporated to dryness and then heated strongly to expel the ammonium salts present. The equations are: NH4Cl NH3(g) + HCl(g) NH4NO3 N2O(g) + 2H2O(g)
  7. 7. • The necessary ammonium ion concentration is then obtained by adding the group IV precipitant, which consists of ammonium chloride and aqueous ammonia in the required concentrations. Ba2+ + CO3 2 BaCO3 (white) Sr2+ + CO3 2 SrCO3 (white) Ca2+ + CO3 2 CaCO3 (white)
  8. 8. BARIUM
  9. 9. SEPARATION and IDENTIFICATION of BARIUM 1. Dissolution of the Carbonates BaCO3 + 2CH3CO2H Ba2+ + 2CH3CO2 + H2O + CO2 2. Separation of Barium from Strontium and Calcium Cr2O7 2 + H2O 2CrO4 + 2H+ 3. Dissolution of Barium Chromate - A solution of 12M HCl is used to bring about the dissolution of BaCrO4
  10. 10. 3. Dissolution of Barium Chromate - A solution of 12M HCl is used to bring about the dissolution of BaCrO4 4. Identification of Barium - the presence of barium ion in the solution is confirmed by precipitating it as barium sulfate, using sulfuric acid as the precipitant. - flame test- yellow green color
  11. 11. STRONTIUM
  12. 12. SEPARATION and IDENTIFICATION of STRONTIUM 1. Separation of Strontium from Calcium Cr2O7 2 + 2NH3 + H2O 2CrO4 2 + 2NH4 + 2. Identification of Strontium - the formation of a fine yellow crystalline precipitate of strontium chromate confirms the presence of strontium - flame test- crimson color
  13. 13. CALCIUM
  14. 14. IDENTIFICATION of CALCIUM • The solution from the strontium chromate separation contains the calcium ion. • The addition of ammonium oxalate precipitates calcium oxalate, CaCrO4, a white crystalline salt. Ca2+ + C2O4 2 CaC2O4 • Flame test- brick red color
  15. 15. THANK YOU!!!  

×