Suggested
Answers on Note (Chapter 20) P.4 - 5
Flowing Mercury Cell流汞電解池
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|
Anode (+) |
Cathode
(-) |
Nature of
electrodes
|
graphite |
flowing mercury |
|
Electrolyte |
Brine (saturated sodium chloride solution) |
|
|
Ions
present |
Cl-, OH- |
Na+, H+ |
|
Discharged
Ion |
Cl- |
Na+ |
|
Ionic Half
Equation |
2Cl-(aq) ¾® Cl2(g) + 2e- |
Na+(aq) + e- ¾® Na(s) |
Sodium metal dissolves in
mercury to form sodium amalgam鈉汞齊.
Na(s)
+ Hg(l) ¾® Na(Hg)
Amalgam then reacts with water
to form hydrogen and sodium hydroxide.
2Na(Hg)
+ 2H2O(l) ¾® 2NaOH(aq) + H2(g) + 2Hg(l)
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|
Anode (+) |
Cathode
(-) |
Nature of
electrodes
|
titanium |
steel |
|
Electrolyte |
Brine (saturated sodium chloride solution) |
|
|
Ions
present |
Cl-, OH- |
Na+, H+ |
|
Discharged
Ion |
Cl- |
H+ |
|
Ionic Half
Equation |
2Cl-(aq) ¾® Cl2(g) + 2e- |
2H+(aq) + 2e- ¾® H2(g) |
Suggested
Answers on Note (Chapter 20) P.8
Laboratory preparation of
chlorine
What is the function of “wet
blue litmus paper”?
Detect
the fullness of chlorine gas in the gas jar.
Turn
from blue to red if the jar is full.
Why “downward delivery”
is used to collect chlorine gas?
Chlorine
gas is denser than air.
Alternative method
of preparing chlorine gas:
2Cl-
¾® Cl2 + 2e-
MnO4-
+ 8H+ + 5e- ¾® Mn2+ + 4H2O
2MnO4-(aq)
+ 16H+(aq) + 10Cl-(aq) ¾® 2Mn2+(aq) + 8H2O(l)
+ 5Cl2(g)
Suggested
Answers on Note (Chapter 20) P.9
Physical properties
Cl2(g)
+ H2O(l) D Cl-(aq) + ClO-(aq)
+ 2H+(aq) Chlorine
water
Cl2(aq)/(g)
+ 2e- ¾® 2Cl-(aq)
Suggested
Answers on Note (Chapter 20) P.12
Displacement Reaction
Cl2(aq)
+ 2KBr(aq) ¾® 2KCl(aq) + Br2(aq)
Cl2(aq)
+ 2KI(aq) ¾® 2KCl(aq) + I2(aq)
Suggested
Answers on Note (Chapter 20) P.13
Bleaching action of chlorine
Cl2(g)
+ H2O(l) Û Cl-(aq) + ClO-(aq)
+ 2H+(aq) Slightly
acidic
2ClO-(aq)
¾¾sunlight¾® 2Cl-(aq) + O2
OCl-(aq)
+ dye ¾® Cl- +
(dye+O)
Suggested
Answers on Note (Chapter 20) P.14 - 18
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1. |
B |
6. |
B |
11. |
C |
16. |
A |
21. |
B |
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2. |
C |
7. |
A |
12. |
D |
17. |
C |
22. |
B |
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3. |
C |
8. |
A |
13. |
D |
18. |
B |
23. |
B |
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4. |
A |
9. |
D |
14. |
C |
19. |
D |
24. |
C |
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5. |
B |
10. |
C |
15. |
A |
20. |
B |
25. |
A |
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26. |
B |
31. |
D |
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27. |
D |
32. |
C |
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28. |
D |
33. |
A |
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29. |
D |
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30. |
D |
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Suggested
Answers on Note (Chapter 20) P.19 - 20
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1. |
A |
6. |
B |
11. |
B |
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2. |
E |
7. |
D |
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3. |
D |
8. |
A |
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4. |
B |
9. |
C |
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5. |
B |
10. |
A |
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