qualitative analysis Flashcards
1
Q
describe the test for ammonium compounds
A
- add NaOH
- gently heat
- place damp red litmus at top of tube (NH3 turns litmus blue)
2
Q
describe the test for hydroxides
A
turns red litmus blue
3
Q
describe the test for carbonates
A
turns limewater cloudy when bubbled through HCl
4
Q
describe the test for sulfates
A
- add HCl to remove carbonates
- add BaCl2
- white ppt forms
5
Q
what is the order for qual analysis?
A
carbonate
sulfate
halide
6
Q
why is there a specific order for qual analysis?
A
prevents false positives
7
Q
iodine in water
A
brown
8
Q
iodine in cyclohexane
A
purple
9
Q
iodine vapour
A
colour
10
Q
bromine in water
A
orange
11
Q
bromine vapour
A
orange/brown
12
Q
chlorine gas
A
pale green
13
Q
silver iodide
A
yellow
14
Q
silver chloride
A
white
15
Q
silver bromide
A
cream
16
Q
phenolphthalein in acid
A
colourless
17
Q
phenolphthalein in alkali
A
pink
18
Q
methyl orange in acid
A
red
19
Q
methyl orange in alkali
A
yellow
20
Q
potassium dichromate
A
orange
21
Q
Cr3+ in sulphuric acid
A
green
22
Q
Fe2+ (aq)
A
pale green
23
Q
Fe3+ (aq)
A
pale yellow
24
Q
Cu2+ (aq)
A
blue
25
Mn2+ (aq)
pale pink
26
Mn(OH)2
beige
27
Cu(OH)2
light blue
28
Cr(OH)3
grey green
29
Fe(OH)2
green
30
Fe(OH)3
brown
31
[Cr(OH6]3-
dark green
32
[Cr(NH3)6]3+
purple
33
[Cu(NH3)4(H2O)2]2+
dark blue
34
end point potassium manganate
permanent pink
35
end point thiosulfate titration
colourless from blue/black
