GROUP II ANIONS Flashcards
Group II Anions contains only
chromate and sulfate ions.
Group II Anions are precipitated by the group reagent
Ba(Ac)2 - Barium Acetate
They are precipitated as _________ and ___________ in slightly basic solution.
BaCrO4 and BaSO4
BasO4 is separated from BaCrO4 by its Solubility in
3M HCl
The chromate ion is confirmed by reprecipitating BaCrO4 from the _________ of the acid solution
centrifugate
Maximum drops of Ba(Ac)2
15
Precipitate may be composed of
BaSO4 and BaCrO4
RESIDUE may be
BaSO4
PRECIPITATE may be
BaCrO4
Precipitating agent of SULFATE ION
3M HCl
Color that confirms the presence of SULFATE IONS
White
Precipitating agent of CHROMATE IONS
2.5 F sodium acetate - NaOAc
Color that indicates the presence of CHROMATE IONS
Yellow
Precipitating agent of Group II
Ba(Ac)2 - Barium Acetate
Group II ions are precipitated with _________ in slightly basic solution.
Barium Acetate
What are the group II precipitates
BaSO4
BaCrO4
The analysis of this group involves no difficulties because the presence of chromate ions shows _______ color.
yellow
Addition of ____ dissolves BaCrO4
HCI
After adding HCl, _____ is the precipitate and ______ is the centrifugate
BaSO4 ~ BaCrO4
Initial detection of Sulfate Ions
White precipitate in the precipitation of Ba(Ac)2
How is the he presence of sulfate confirmed?
Addition of more HCI (but not too much, as acid can shift equilibrium to the left, dissolving more barium sulphate) dissolves more BaCrO4. Thus if precipitate will not dissolve, which is BaSO4, sulphate is present.
How is the presence of Chromate ions confirmed?
The addition of sodium acetate to the acidic chromic solution lowers the Hydrogen ion concentration sufficiently to permit reprecipitation of BaCrO4, the yellow precipitate.
