Jessa S. AriñoBSE-4B

Central Bicol State University of Agriculture

ANALYSIS OF GROUP IV CATIONS

Group Separations in Qualitative Analysis

Group Separations in Qualitative Analysis

PRECIPITATION OF GROUP 4 CATIONS

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.

• 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.

• 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)

• 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+ + CO32 BaCO3 (white)

Sr2+ + CO32 SrCO3 (white)

Ca2+ + CO32 CaCO3 (white)

The technology of cage culture is relatively cheap and easy to run. The materials used in construction are indigenous and readily available like the bamboo supports. Filipinos are used to working with bamboo. In addition, grouper fry can now be produced in hatcheries or transported from areas where fry collection is an established industry, and there are a lot of places in the country where this is so.

BARIUM

SEPARATION and IDENTIFICATION

of BARIUM 1. Dissolution of the Carbonates

BaCO3 + 2CH3CO2H Ba2+ + 2CH3CO2 + H2O + CO2

2. Separation of Barium from Strontium

and Calcium

Cr2O72

+ H2O 2CrO4 + 2H+

3. Dissolution of Barium Chromate

- A solution of 12M HCl is used to bring about the dissolution of BaCrO4

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

The technology of cage culture is relatively cheap and easy to run. The materials used in construction are indigenous and readily available like the bamboo supports. Filipinos are used to working with bamboo. In addition, grouper fry can now be produced in hatcheries or transported from areas where fry collection is an established industry, and there are a lot of places in the country where this is so.

STRONTIUM

SEPARATION and IDENTIFICATION of STRONTIUM

1. Separation of Strontium from Calcium

Cr2O72

+ 2NH3 + H2O 2CrO42

+ 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

The technology of cage culture is relatively cheap and easy to run. The materials used in construction are indigenous and readily available like the bamboo supports. Filipinos are used to working with bamboo. In addition, grouper fry can now be produced in hatcheries or transported from areas where fry collection is an established industry, and there are a lot of places in the country where this is so.

CALCIUM

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+ + C2O42 CaC2O4

• Flame test- brick red color

THANK YOU!!!