1. Al(OH)3, Cr(OH)3, Fe(OH)3, NiS, CoS, MnS, ZnS
SUPERNATANT A: (Fe3+, Al3+, Cr3+, Mn2+, Zn2+ )
dark green color Co +2
Transfer to a clean test tube
10 drops of HNO3
pinches of spatula sodium bismuthate (NaBiO3) from the side of the tube
PRECIPITATE A: CoS, NiS
III. GROUP CATIONS
20 drops of sample
10 drops of 4 M NH4Cl
Dropwise 2 M NH4OH
check the basicity of the solution with a litmus paper.
20 drops of NH4OH eklenir.
Heat the solution for 5 min at water bath and add 20 drops of thioacetamide solution
COMMON PRECIPITATE
Al(OH)3, Cr(OH)3, Fe(OH)3, NiS, CoS, MnS, ZnS
Wash several times with 0.1 M NH4Cl
Add 20 drops of 6 M HCl
Centrifuge and separate the supernatant A and the precipitate A.
aken into cruicible, heated on bunsen burber till the solute part evaporates
20 drops of aqua regia (15 drops of 6 M HCl + 5 drops of 6 M HNO3) to dissolve the precipitate.
Add 2 M NH4OH check the basicity with red litmus paper.
2 drops of 6 M NaOH
2 drops of dimethyl glyoxime
Add 0.1 M (K4[Fe(CN)6])
SUPERNATANT C: Cr3+, Zn2+
Violet color,
Mn2+
white aluminum hydroxide (Al(OH)3)
2 drops of thioacetamide solution heat it up in the water bath with stirring for 5 minutes until the white precipitate is visible.
20 drops 2 M CH3COOH
pinches of spatula of sodium acetate (NaCH3COO)
Heat the solution in a water bath for 20 min
add 2 drops of 0.5 M barium chloride (BaCl2) solution to the hot solution.
20 drops of 6 M NaOH
20 drops of 3%
H2O2 Centrifuge and separate supernatant B and the precipitate B.
PRECIPITATE B Fe(OH)3, MnO2
20 drops of HNO3
add NH4OH until it is basic.
Centrifuge and separate the supernatant C and the precipitate C
SUPERNATANT B: Zn2+, Al3+, Cr3+
10 drops of 0,1 M (K4[Fe(CN)6])
rose color Ni +2
prussian blue precipitate Fe3+
PRECIPITATE C
PRECIPITATE D
Yellow precipitate barium chromate BaCrO4
SUPERNATANT D
dirty white precipitate
ZnS
Divide the sample into two