Inorganic Qualitative Tests Flashcards
(21 cards)
Test and result for halide ions
Add AgNO3, precipitates form:
AgCl is white - dissolves in dilute NH3
AgBr is cream - only dissolves in conc NH3
AgI is yellow - does not dissolve in any NH3
Test for CO3 2- (carbonate)
Add acid such as HCl, (or vice versa) - effervescence (CO2 forms) - prove it is CO2 as it turns limewater cloudy
Test for Sulfates
Add Barium ions (maybe BaNO3), a white precipitate forming indicates presence of Sulfate
Test for ammonium
Add NaOH to form NH3. Test for NH3 - it turns red litmus paper blue
[Cu(H20)6]2+ colour?
Pale blue
How do you get Cu(OH)2 (s) and what colour is it
NH3 or NaOH drop wise to Cu2+
Pale blue precipitate
[Cu(NH3)4(H2O)2]2+
How do you get it
What colour is it
Add excess NH3 to Cu2+
Dark blue
[CuCl4]2-
How do you get it
What colour is it
Excess HCl to Cu2+
Yellow
? + ? —> Cu+
Colour?
Cu2+ + I-
White precipitate: CuI
Brown iodine water
[Cr(H2O)6]3+
Colour?
Pale purple
Can appear green due to impurities in solution
Cr(OH)3 (s)
How do you get it
What colour
Add NH3/NaOH dropwise
Dark green precipitate
[Cr(NH3)6]3+
How do you get it
What colour
Add excess NH3 to Cr3+
Purple
[Cr(OH)6]3-
How do you get it
What colour
Add excess OH- to Cr(OH)3 (s)
Dark green
Cr2O7 2-
Colour?
Orange
CrO4 2-
How do you get it
What colour
(Oxidation of Cr3+) add hot alkaline H2O2
Yellow
[Mn(H2O)6]2+
Colour?
Pale pink
Mn(OH)2 (s)
How do you get it
What colour
Add NaOH dropwise to Mn2+ (aq)
Pale brown precipitate
[Fe(H2O)6]2+
Colour?
Pale green
Fe(OH)2 (s)
How do you get it
What colour
NaOH dropwise to Fe2+ (aq)
Dark green precipitate
[Fe(H2O)6]3+
Colour?
Yellow
Fe(OH)3 (s)
How do you get it
What colour
NaOH dropwise to Fe3+ (aq)
Orange/brown precipitate
