Transition metals Flashcards
(61 cards)
1
Q
I2
A
brown solution
2
Q
CrO4 2-
A
yellow solution
3
Q
AgI
A
Yellow ppt that does not dissolve in conc NH3
4
Q
AgBr
A
Cream ppt that does dissolve in conc NH3
5
Q
AgCl
A
White ppt that does dissolve in conc NH3
6
Q
MnO4- and Fe2+ colour change
A
purple to pale pink
7
Q
Mn(OH)2
A
Light brown PPT which darkens on standing
8
Q
[Cr(NH3)6]3+
A
Purple solution
9
Q
Cr2O7 2-
A
orange solution
10
Q
[Cu(H2O)6]2+
A
Pale blue solution
11
Q
[Fe(H2O)6]2+
A
Pale green solution
12
Q
[Fe(H2O)6]3+
A
yellow solution
13
Q
[Mn(H2O)6]2+
A
pale pink solution
14
Q
[Cr(H2O)6]3+
A
Pale purple solution
15
Q
Cu(OH)2
A
pale blue ppt
16
Q
Fe(OH)2
A
Green PPT which darkens on standing
17
Q
Fe(OH)3
A
Orange brown ppt
18
Q
Mn(OH)2
A
Light brown PPT which darkens on standing
19
Q
Cr(OH)3
A
grey-green ppt
20
Q
[Cr(OH)6]3-
A
dark green solution
21
Q
Cr2O7 2-
A
orange solution
22
Q
[Cu(NH3)4(H2O)2]2+
A
dark blue solution
23
Q
[CuCl4]2-
A
yellow solution
24
Q
[Cr(NH3)6]3+
A
purple solution
25
Permanganate ion
MnO4-
26
Dichromate ion
Cr2O7 2-
27
MnO4- and Fe2+ products
Mn2+ and Fe3+
27
Chromate ion
CrO4 2-
28
Cu2+ and I- products
CuI(s) and I2
29
CuI(s)
white ppt
30
what colour is Fe2+(aq) and Fe3+(aq)
pale green and yellow
31
what do you need for the interconversion between Fe2+ and Fe3+, and what kind of reaction is it?
acidified potassium manganate
Fe2+ is oxidised to Fe3+
32
What are the half equations for the interconversion between Fe2+ and Fe3+
(MnO4) - + 8H+ + 5e-
-> Mn2+ + 4H2O (MANGANATE IS REDUCED)
Fe2+ -> Fe3+ + e- (IRON IS OXIDISED)
(MnO4)- + 8H+ + 5Fe2+ --> Mn2+ + 4H2O + 5 Fe3+
33
what do you need for the interconversion between Fe3+ and Fe2+, and what kind of reaction is it?
Iodide ions
Fe3+ is reduced to Fe2+
34
What are the half equations for the interconversion between Fe3+ and Fe2+
2I- --> I2 + 2e- (IODIDE IS OXIDISED)
Fe3+ + e- --> Fe2+ (IRON IS REDUCED)
2I- + 2Fe3+ -> 2Fe2+ + I2
35
what colour is the Cr3+ ion in [Cr(OH)6]3- and (CrO4)2-
dark green, yellow
36
what do you need for the interconversion between CrO3+ and (CrO4)2- , and what kind of reaction is it?
need to warm hydrogen peroxide in alkaline conditions.
Cr3+ is oxidised to (CrO4)2-
37
What are the half equations for the interconversion between Cr3+ and (CrO4)2-
H2O2 + 2e- --> 2OH-
Oxygen is reduced.
2[Cr(OH)6] 3- + 4OH- --> 2(CrO4)2- + 8H2O + 6e-
Chromium is oxidised.
Full equation
3Н2O2 + 2[Cr(OH)6] 3- --> 2OH- + 2(CrO4)2- + 8H2O
38
what do you need to convert (CrO4)2- to (Cr2O7)2-, what is the equation
dilute sulfuric acid
2(CrO4)2- + 2H+ --> (Cr2O7)2- +H2O
39
what do you need for the interconversion between (Cr2O7)2- and CrO3+ , and what kind of reaction is it?
acidified zinc
(Cr2O7)2- is reduced to CrO3+
40
What are the half equations for the interconversion between (Cr2O7)2- and CrO3+
Zn --> Zn2+ + 2e-
Zinc is oxidised.
(Cr2O7)2- + 14H+ + 6e- --> 2Cr3+ + 7H20
Chromium is reduced.
(Cr2O7)2- +14H+ +3Zn → 2Cr3+ +7H2O + 3Zn3+
41
what colour is Cu2+ and CuI
pale blue
off white
42
what do you need for the reduction of Cu2+
iodide ions
43
colour change when add NH3 or OH- to Cu2+
blue solution to ppt
44
colour change when add NH3 or OH- to Fe2+
green solution to ppt
45
colour change when add NH3 or OH- to Mn2+
pink solution to brown ppt
46
colour change when add NH3 or OH- to Cr3+
violet solution to green ppt
47
colour change when add NH3 or OH- to Fe3+
yellow solution to brown ppt
48
colour change when add excess NH3 to Cu2+
ppt re-dissolves to give blue solution
49
colour change when add excess NH3 to Fe2+
no change
50
colour change when add excess NH3 to Mn2+
no change
51
colour change when add excess NH3 to Cr3+
ppt dissolves to give purple solution
52
colour change when add excess NH3 to Fe3+
no change
53
colour change when add excess OH- to Cu2+
no change
54
colour change when add excess OH- to Fe2+
no change
55
colour change when add excess OH- to Mn2+
no change
56
colour change when add excess OH- to Cr3+
ppt dissolves to give green solution
57
colour change when add excess OH- to Fe3+
no change
58
test for ammonium ions
add NaOH to sample and warm gently, if distinctive smell (ammonia gas) and if turns red litmus paper blue, this is a positive test
59
test for carbonate ions
add strong acid to sample, pass gas produced through limewater, if turn milky positive test
60
test for sulfate ions
add dilute HCl and barium chloride, if white ppt forms barium sulphate is produced so a positive test
