1
Oxidation and Reduction Reactions
Period/Topic
Worksheets
1.
Oxidation, Reduction, Agents, & Reactions.
2.
Lab: The Strength of Oxidizing Agents.
3.
Oxidation Numbers Spontaneous Reactions
2
4.
Oxidation Numbers, Application to Reactions.
3
5.
Balancing Redox Half Reactions Acid/Base.
4
6.
Balancing Redox Reactions in Acid/Base.
5
7.
Standard Potentials Using Chart.
6
8.
Electrochemical Cells.
7
9.
Electrochemical Cells Lab.
10.
Electrolytic Cells.
11.
Electrolytic Cells Lab.
12.
Application of Electrochemical Cells
13.
Quiz
1
1
2
3
8
4
Application of Electrolytic Cells
9
5
14.
Corrosion, Redox Titrations, Breathalyzer
10
6
15.
Review.
Internet Review
Practice Test 1
16.
Review
Practice Test 2
17.
Test.
2
Worksheet #1
Redox Half Reactions and Reactions
Define each
1.
2.
3.
4.
Oxidation
Reduction
Oxidizing agent
Reducing agent
Write half reactions for each of the following atoms or ions. Label each as oxidation or
reduction.
5.
Al
6.
S
7.
O-2
8.
Ba2+
9.
N3-
10.
Br2
11.
P
12.
Ca
13
Ga3+
14.
S
15.
H2
16.
H+
17.
F-
18.
P3-
3
Balance each spontaneous redox equation. Identify the entities reduced and oxidized. State the
reducing agent and the oxidizing agent.
19.
Al
&
Zn2+
20.
F2
&
O2-
21.
O2
&
Ca
22.
Al3+
&
Li
Write the oxidation and reduction reactions for each redox reaction. The first one is done for you.
23.
24.
Fe2+
+
⇄
Co
Oxidation:
Co

Co2+
+
2e-
Reduction:
Fe2+
+
2e-

Fe
3 Ag+
Co2+
+
Fe
+
Ni
⇄
Ni3+
+
3 Ag
+
Pb
⇄
Pb2+
+
Cu
Oxidation:
Reduction:
25.
Cu2+
Oxidation:
Reduction:
4
26.
+
O2
+
2 Sn
⇄
O2-
+
2 F-
⇄
Co
+
2 Sn2+
Oxidation:
Reduction:
Co2+
27.
F2
Oxidation:
Reduction:
28. There are nine formulas for oxidizing agents from questions 19 to 28. List them all. Only
consider formulas that are on the left side of any equation. The first one is done for you.
Zn2+
29. There are nine formulas for reducing agents from questions 19 to 28. List them all. Only
consider formulas that are on the left side of any equation. The first one is done for you.
Al
Worksheet #2
1.
Redox Half Reactions and Reactions
State the Oxidation Number of each of the elements that is underlined.
a) NH3
_____
b) H2SO4
_____
c) ZnSO3
_____
d) Al(OH)3
_____
e) Na
_____
f) Cl2
_____
g) AgNO3
_____
h) ClO4-
_____
i) SO2
_____
j) K2Cr2O4
_____
k) Ca(ClO3)2
_____
l) K2Cr2O7
_____
m) HPO32-
_____
n) HClO
_____
5
2.
o) MnO2
_____
p) KClO3
_____
q) PbO2
_____
r) PbSO4
_____
s) K2SO4
_____
t) NH4+
_____
u) Na2O2
_____
v) FeO
_____
w) Fe2O3
_____
x) SiO44-
_____
y) NaIO3
_____
z) ClO3-
_____
aa) NO3-
_____
bb) Cr(OH)4
_____
cc) CaH2
_____
dd) Pt(H2O)5(OH)2+ _____
ee) Fe(H2O)63+
_____
ff) CH3COOH
_____
What is the oxidation number of carbon in each of the following substances?
a) CO
_____
b) C
_____
c) CO2
_____
d) CO32-
_____
e) C2H6
_____
f) CH3OH
_____
3.
For each of the following reactants, identify: the oxidizing agent, the reducing agent, the
substance oxidized and the substance reduced. Use oxidation numbers.
a)
Cu2+ (aq)
b)
+
→
Zn (s)
Substance oxidized
Oxidizing agent
_____
_____
Cl2 (g) +
→
2 Na (s)
Substance oxidized
Oxidizing agent
_____
_____
Cu(s)
+
Zn2+ (aq)
Substance reduced
Reducing agent
2 Na+ (aq)
+
_____
_____
2 Cl- (aq)
Substance reduced
Reducing agent
____
_____
6
Worksheet # 3
Spontaneous and Non-spontaneous Redox Reactions
Describe each reaction as spontaneous or non-spontaneous.
→
Fe2+
+
Au
→
Fe2+
+
Pb2+
→
F2
S2O82- + Pb
→
2SO42-
5.
Cu2+
+ 2Br-
→
Cu
6.
Sn2+
+ Br2
→
Sn4+
+ 2Br-
7.
Pb2+
+ Fe2+
→
Fe3+
+ Pb
8.
Can you keep 1 M HCl in an iron container? If the answer is no, write a balanced
equation for the reaction that would occur.
9.
Can you keep 1 M HCl in an Ag container? If the answer is no, write a balanced equation
for the reaction that would occur.
10.
Can you keep 1 M HNO3 in an Ag container? If the answer is no, write a balanced
equation for the reaction that would occur. (HNO3 consists of two ions H+ and NO3-)
11.
Can you keep 1 M HNO3 in an Au container? If the answer is no, write a balanced
equation for the reaction that would occur. (Remember, HNO3 consists of two ions H+
and NO3-)
1.
Au3+
2.
Pb
+
3.
Cl2
+
4.
+
Fe3+
Fe3+
F-
+
2Cl+ Pb2+
+ Br2
7
12.
Circle each formula that is able to lose an electron
Cl-
O2
13.
Determine the oxidation number for the element underlined.
PbSO4
HP032CaH2
NaIO3
14.
Na+
Fe
Al3+
__________
__________
__________
__________
+
→
Zn
ClO3Na2O2
Al2(SO4)3
C4H12
__________
__________
__________
__________
Al
Zn2+
+
Substance oxidized _______ Oxidizing agent ________
15.
Cr2O72-
+
ClO2- →
Cr3+
+
ClO4-
Substance reduced ________ Oxidizing agent ________
16.
State the Oxidation Number of each of the elements that is underlined.
a) NH3
c) ZnCO3
e) Na
__________
__________
__________
b) H2SO4
d) Al(OH)3
f) Cl2
17.
Balance the redox equation using the half reaction method.
Al
&
AgNO3
18.
Circle each formula that is able to lose an electron
O2
Cl-
Fe
Na+
Determine the oxidation number for the element underlined.
19.
20.
21.
22.
23.
24.
25.
26.
PbSO4
ClO3HPO32Na202
CaH2
NaIO3
C4H12
Al2(SO4)3
__________
__________
__________
__________
__________
__________
__________
__________
__________
__________
__________
8
27.
Al3+
+
Zn
Substance oxidized
28.
Al
__________
ClO2- →
Cr2O72- +
Substance reduced
29.
→
Cr3+
__________
3As2O3
Zn2+
Oxidizing agent
+
Worksheet # 4
__________
+ 2H+
Reducing agent
+ 4NO3- + 7H2O + 4 H+ → 6H3AsO4
Substance reduced __________
__________
ClO4-
Oxidizing agent
O3 + H2O + SO2 → SO42- + O2
Substance oxidized__________
30.
+
Reducing agent
__________
+ 4NO
__________
Balancing Redox Reactions
Balance each of the following half-cell reactions. (In each case assume that the reaction takes
place in an ACIDIC solution.) Also, state whether the reaction is oxidation or reduction.
→
1.
S2O32-
SO42-
2.
MnO4-
3.
As
→
AsO43-
4.
Cr3+
→
Cr2O72-
5.
Pb2+
→
PbO2
6.
SO42-
→
S
→
Mn2+
9
7.
NO3-
→
NO
8.
NO3-
→
NH4+
9.
BrO3-
→
Br2
Balancing Half Cell Reactions
Balance in basic solution.
10.
NO3-
→
NO
11.
MnO4-
→
Mn2+
12.
As
→
AsO43-
13.
Cr3+
→
Cr2O72-
14.
Pb2+
→
PbO2
15.
SO42-
→
S
16.
S2O32-
→
SO42-
17.
NO3-
→
NH4+
10
→
BrO3-
18.
Br2
19. Determine if each of the following changes is oxidation, reduction or neither.
20.
SO32-
→
SO42-
________________
CaO
→
Ca
________________
CrO42-
→
Cr2O72-
________________
CrO42-
→
Cr3+
________________
2I-
→
I2
________________
IO3-
→
I2
________________
MnO4-
→
Mn2+
________________
ClO2-
→
ClO-
________________
Cr2O72-
+
Fe2+
Substance oxidized
Oxidizing agent
Worksheet # 5
→
Cr3+
_____
_____
+
Fe3+
Substance reduced
Reducing agent
_____
_____
Balancing Redox Reactions in Acid and Basic Solution
Balance each redox equation. Assume all are spontaneous. Use the half reaction method.
1.
O2-
+
F2
2.
Al
+
O2
3.
K
+
Zn+2
Balance each half reaction in basic solution.
4.
Cr2O72 -
→
Cr3+
11
5.
NO
→
NO3-
6.
SO42-
→
SO2
7.
MnO2
→
Mn2O3
Balance each redox reaction in acid solution using the half reaction method.
8.
H2O2 +
Cr2O72-
→
9.
TeO32- +
N2O4
→
10.
ReO4- +
IO-
→
11.
PbO2 +
I2
→
12.
→
As
O2
Te
+
+
IO3-
NO3-
+
Pb2+
+
IO3-
H2AsO4-
+
AsH3
Balance each redox reaction in basic solution using the half reaction method.
13.
O2
+
Cr3+
→
H2O2
+
Cr2O72-
Cr3+
Re
12
14.
Te
+
NO3- →
15.
IO3-
+
Re
→
16.
Pb2+
+
IO3-
→
17.
Cr2O72- +
Hg
→
TeO32-
ReO4-
+
+
PbO2
Hg2+
IO-
+
+
N2O4
I2
Cr3+
State of the change represents oxidation, reduction or neither. Use oxidation #s. Remember that
if the oxidation # increases it means oxidation and when it decreases it mean reduction!
18.
MnO2
→
Mn2O3
19.
NH3
→
NO2
20.
HClO4
→
HCl
21.
O2
→
O2-
22.
P2O5
→
P4H10
+
H2O
13
Determine the oxidation number
23.
H2S O4
22.
HS O4-
24.
P4
23.
NaH
25.
U O3
24.
Na2O 2
26.
U 2O5
25.
P b SO4
Worksheet # 6
1.
Review
Describe each in your own words
a) Oxidation
b) Reduction
c) Oxidizing agent
d) Reducing agent
2. Write half reactions for each. Describe as oxidation or reduction. Circle all oxidizing agents.
a)
b)
c)
d)
e)
f)
3.
Na
Ca
Al3+
F1N2
O2-
Write the reaction between the following: Use the half reaction method.
a)
Ca
+
Al(NO3)3
b)
Sn
+
AgNO3
c)
Sn
+
Au(NO3)3
4.
Circle each reducing agent:
Cu
5.
Circle each oxidizing agent: F-
Cu+
Al
Al3+
F
O2-
O2
14
6. Ni+2 reacts with Mn, however, Al+3 does not react with Mn. Rank the oxidizing agents in
order of decreasing strength. Rank the reducing agents in order of decreasing strength.
7.
Ag+ reacts with Pb, however, Ca+2 does not react with Pb. Rank the reducing agents in
order of decreasing strength. Rank the oxidizing agents in order of decreasing strength.
8.
Cl2 reacts with Ag, however, Ag does not react with Mg+2. Rank the oxidizing agents in
order of decreasing strength. Rank the reducing agents in order of decreasing strength.
9.
Ni+2 reacts with Mn, however, Al+3 does not react with Mn. Rank the reducing agents in
order of decreasing strength. Rank the oxidizing agents in order of decreasing strength.
10.
Cl2 reacts with Br-, however, I2 does not react with Br-. Rank the oxidizing agents in
order of decreasing strength. Rank the reducing agents in order of decreasing strength.
Classify as oxidation, reduction or neither.
11.
SO42-
→
S2-
12.
MnO2
→
MnO4-
13.
Cr2O72-
→
CrO42-
14.
IO3-
→
I2
15
15.
Given the following lab data
SnCl2
Ni(NO3)2
Cr(NO3)3
16.
Ni
Fe
Fe
Spontaneous
Spontaneous
Non spontaneous.
i)
Write three balanced equations.
ii)
Rank the oxidizing agents in decreasing order of strength.
iii)
Rank the reducing agents in decreasing order of strength.
iv)
Will SnCl2 react with Cr? Explain?
v)
Will Fe2+ react with Sn?
Determine the oxidizing and reducing agent. Balance in acidic solution.
MnO4- +
17.
&
&
&
H2S
→
S
+
MnO
Determine the oxidizing and reducing agent. Balance in acidic solution.
SO42- +
Br2
→
S2O32- +
BrO3-
16
MnO4-
Balance in basic solution
19.
Describe as spontaneous or non-spontaneous. Use your reduction potential chart.
a)
c)
20.
ZnCl2 &
Br2
Cu
&
+
2+
Fe
H2S
→
18.
b)
d)
S
CuCl2 &
H2S
+
MnO
NaCl
&
Al3+
Can you keep HCl in a Zn container? Explain? What about an Au container?
Balance in basic solution
21.
SO42- +
Br2
→
S2O32- +
BrO3-
Classify as an oxidizing agent, reducing agent or both based on its position on the table.
State the Eo or voltage of its position. Some of these are both, so state two voltages and indicate
that it can be an oxidizing and reducing agent.
e.g.
MnO422.
23.
24.
25.
(in acid)
Br2
Fe2+
MnO4- (water)
Ni
oxidizing agent
_________________
_________________
_________________
_________________
1.51 V
_________________
_________________
_________________
_________________
26.
27.
Cr3+
H2O
_________________
_________________
_________________
_________________
Indicate as spontaneous or non-spontaneous.
28.
29.
30.
MnO4- (Alkaline) & Fe2+
HNO3
&
Ag
HCl
&
Mg
17
Write each oxidation and reduction half reaction for each question above. Determine the Eo for
each. Calculate the Eo for the overall reaction.
34.
35.
36.
Worksheet # 7
Electrochemical Cells
1.
Oxidation is when electrons are
.
2.
Reduction is when electrons are
.
3.
The reducing agent undergoes
.
4.
The oxidizing agent undergoes
.
5.
A negative voltage means the reaction is
6.
In an electrochemical cell electrons exit the electrode which is
7.
In an electrochemical cell the reduction reaction is
oxidation reaction is
.
8.
The cathode is the site of
9.
Anions migrate to the
10.
Anions have a
.
Zn / Zn(NO3)2
and cations migrate to the
charge and cations have a
ll
on the chart, while the
and the anode is the site of
Draw and completely analyze each electrochemical cell.
11.
.
Cu / Cu(NO3)2
charge.
.
.
18
12.
Ag / AgNO3
ll
H2 / HCl
Worksheet # 8
Electrolytic Cells
1.
In an electrolytic cell, reduction occurs at the
occurs at the
electrode.
2.
If there are two possible reduction reactions, the
3.
For reduction, the chart is read from
to
4.
For oxidation, the chart is read from
voltage is
.
to
5.
If there are two possible oxidation reactions, the
6.
Corrosion of a metal is
7.
Electrolysis
8.
Electrochemical cells
9.
Electrolytic cells
10.
What is the standard reference cell?
Molten NaCl
one on the chart occurs.
.
and the sign of the
one on the chart occurs.
.
electrical energy.
electrical energy.
electrical energy.
Draw and completely analyze each electrolytic cell.
11.
electrode and oxidation
Eo =
v
19
12.
Aqueous Na2SO4
13.
Liquid K2O
14.
1.0 M LiI
15.
250.0 mL of 0.200 M MnO4- reacts with excess SO3-2. How many grams of
MnO2 are produced? This is Chemistry 11 stoichiometry.
2MnO4- + 3SO32- + H2O → 2MnO2 + 3SO42- + 2OH-
16.
Determine the oxidation number for each underlined atom.
MnO2
Cr2O72IO3C2O42Al(NO3)3
17.
Describe each term:
Salt bridge
Electrolyte
Anode
Cathode
Spontaneous
Electron affinity
20
18.
What would happen if you used an aluminum spoon to stir a solution of FeSO4(aq)? Write
a reaction and calculate Eo.
19.
Draw an electrochemical cell using Cu and Ag electrodes.
20.
250.0 mL of 0.500 M MnO4- are required to titrate a 100.0 ml sample of SO3-2. Calculate
the [SO3-2]
2MnO4- + 3SO32- + H2O → 2MnO2 + 3SO42- + 2OH-
21.
How is the breathalyzer reaction used to determine blood alcohol content (you might
need to look this up in your textbook?
22.
2H+ + Mg → Mg2+ +H2
Oxidizing agent__________
Worksheet # 9
Reducing agent_________
Electrolytic, Electrochemical Cells & Application
Determine the half reactions for each cell and the cell voltage or minimum theoretical voltage
and overall equation.
1.
Ag / Pb electrochemical cell.
Anode:
Anode reaction:
Overall reaction:
Cathode:
Cathode reaction:
Voltage:
21
2.
ZnCl2(l) electrolytic cell (electrowinning)
Anode:
Anode reaction:
Overall reaction:
3.
CuSO4(aq) electrolytic cell (electrowinning)
Anode:
Anode reaction:
Overall reaction:
4.
Cathode:
Cathode reaction:
MTV:
The electrolysis of 1M NaI (electrowinning)
Anode:
Anode reaction:
Overall reaction:
5.
Cathode:
Cathode reaction:
MTV:
Cathode:
Cathode reaction:
MTV:
The reaction needed to make Al. The electrolyte is
(molten or aqueous).
and its phase is
To lower the mp. from 2000 oC to 800 oC
is used.
Anode:
Cathode:
Anode reaction:
Cathode reaction:
Overall reaction:
6.
The reaction needed to electroplate a copper penny with silver.
Anode:
Anode reaction:
Cathode:
Cathode reaction:
Possible Electrolyte:
7.
The reaction needed to nickel plate a copper penny.
Anode:
Anode reaction:
Cathode:
Cathode reaction:
Possible Electrolyte:
8.
The reaction used in the electrorefining of lead.
Anode:
Anode reaction:
Possible Electrolyte:
Cathode:
Cathode reaction:
22
Worksheet # 10 Electrolytic, Electrochemical Cells, Corrosion, & Cathodic Protection
Determine the half reactions for each cell and the cell voltage or minimum theoretical voltage.
1.
Zn / Mg electrochemical cell
Anode:
Anode reaction:
Overall reaction:
Cathode:
Cathode reaction:
Voltage:
2.
The electrolytic cell used to produce Al.
Phase (aqueous or molten)
Cathode:
Cathode reaction:
3.
Electrolyte:
Anode:
Anode reaction:
Overall reaction:
The electrolysis KI(aq)
Anode:
Anode reaction:
Overall reaction:
Cathode:
Cathode reaction:
MTV
4.
The electrorefining of Pb
Anode:
Anode reaction:
5.
Cathode:
Cathode reaction:
Nickel plating a iron nail.
Anode:
Cathode:
Anode reaction:
Cathode reaction:
Electrolyte
The -ve side of the power supply is connected to the
6.
Draw an Ag/ Zn electrochemical cell.
7.
Draw a KF(l) electrolytic cell.
23
8.
Draw a KF(aq) electrolytic cell.
9.
Draw a FeI2(aq) electrolytic cell.
10.
Draw a Cd/Pb electrochemical cell. Cd is not on the reduction chart, however, the Cd
electrode gains mass and the total cell potential is 0.5 v. Determine the half-cell potential
for Cd.
11.
Write the overall reaction and describe the anode and cathode for a Zn/C, fuel, alkaline
and lead/acid cell.
12.
2HIO3 +
5H2SO3
→
oxidizing agent
substance reduced
13.
What is the electrolyte in a fuel cell?
14.
What is the fuel in a fuel cell?
I2 +
5H2SO4
+
substance oxidized
reducing agent
H2O
24
15.
Describe the differences and similarities between an electrolytic and electrochemical cell.
16.
Describe and give two examples of electrowinning.
17.
Describe and give one example of electrorefining.
18.
List three metals that can be won from aqueous solution.
19.
List three metals that cannot be won from aqueous solution.
20.
List the electrolyte in each of the following.
Fuel cell,
Alkaline battery
Dry Cell (Leclanche)
Lead acid battery
21.
State two metals that can be used to cathodically protect Fe. Describe how they protect
iron from corrosion.
22.
Write the half reaction that describes the corrosion of iron.
23.
Write the half reaction that describes the reduction reaction that occurs when iron
corrodes in air and water.
24.
Why does iron corrode faster in salt water?
25
25.
Write the anode and cathode reaction in an electrolytic cell with a CaCl2(l) electrolyte.
26.
Explain why you would choose Zn or Cu to cathodically protect iron?
27.
Choose a suitable redox reactant to oxidize Cl- to ClO4- in a redox titration.
28.
Describe as an electrochemical or electrolytic cell:
a) Fuel cell
b) Charging a car battery
c) Discharging a car battery
d) Ni plating
e) Industrial Al production
f) Cl2 production
29.
Write the anode and cathode reactions for each of the above processes.
30.
Al and AgNO3(aq) are mixed and the surface of the Al darkens. List the two oxidizing
agents in decreasing strength. List the two reducing agents in decreasing strength.
26
31.
Analyze This
Label each anode and cathode.
Write each anode and cathode reaction.
Indicate the ion migration in each cell.
Determine the initial cell voltage of the electrochemical cell.
Determine the MTV for the electrolytic cell.
Will electrolysis occur?
Indicate electron flow.
Indicate all electrodes that gain mass.
Indicate all electrodes that lose mass.
What happens to [NO3-] in the Mg half-cell?
What happens to the [Ag+] in the Ag half-cell?
What happens to [Mg2+] in the Mg half-cell?
What is the equilibrium electrochemical cell potential?
What chemical is made at the Pt electrode on the right?
What chemicals are made at the Pt electrode on the left?
1.0 M KNO3
Ag
Mg
1 M Mg(NO3)2
1 M AgNO3
Pt
Pt
1 M CuSO4
27
Redox
Quiz #1
Agents, Spontaneous Reactions, Oxidation #.
1.
In a redox reaction, the species that loses electrons
A.
is oxidized
B.
is called the cathode
C.
gains mass at the electrode
D.
decreases in oxidation number
2.
Which of the following is the strongest oxidizing agent?
A.
Cu2+
B.
Pb2+
C.
Ni2+
D.
Sn2+
3.
Metallic platinum reacts spontaneously with Au3+(aq) but does not react with
Ag+(aq).
The metals, in order of increasing strength as reducing agents, are
A.
Ag, Pt, Au
B.
Pt, Au, Ag
C.
Au, Ag, Pt
D.
Au, Pt, Ag
4.
The oxidizing agent in the reaction below is
MnO4- + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O
A.
Fe2+
B.
Fe3+
C.
Mn2+
D.
MnO4-
5.
MnO4- + 5Fe2+ + 8H+ → Mn2+ + 5Fe3+ + 4H2O
During the reaction, electrons transfer from
A.
Fe3+ to Fe2+
B.
Fe2+ to MnO4C.
MnO4- to Fe2+
D.
MnO4- to Mn2+
6.
As an element is oxidized, its oxidation number
A.
increases as electrons are lost
B.
decreases as electrons are lost
C.
increases as electrons are gained
D.
decreases as electrons are gained
7.
A solution of 1.0 M Pb(NO3)2 will not react with a container made of
A.
Cu
B.
Fe
C.
Sn
D.
Zn
8.
A spontaneous redox reaction occurs when a piece of iron is placed in 1.0 M
CuSO4. The reducing agent is
A.
Fe
B.
Cu2+
C.
H2O
D.
SO42-
28
9.
A substance is oxidized when it
A.
loses protons
B.
gains protons
C.
loses electrons
D.
gains electrons
10.
A strip of titanium, Ti, is placed in 1.0 M Sn(NO 3)2. The shiny surface of the
titanium darkens, indication that a reaction has
occurred. From this observation it may be concluded that
A.
Ti2+ is a weaker reducing agent than Sn2+
B.
Ti2+ is a weaker oxidizing agent than Sn2+
C.
Ti2+ is a stronger reducing agent than Sn2+
D.
Ti2+ is a stronger oxidizing agent than Sn2+
11.
Consider the following redox reaction : Hg2+ + Cu → Hg + Cu2+ . In this
reaction, Hg2+ is a
A.
weaker reducing agent than Cu2+
B.
weaker oxidizing agent than Cu2+
C.
stronger reducing agent than Cu2+
D.
stronger oxidizing agent than Cu2+
12.
The species which gains electrons in a redox reaction
A.
loses mass
B.
is oxidized
C.
is the oxidizing agent
D.
increases in oxidization number
13.
Samples of Uranium, Vanadium and Yttrium (U, V, Y) were placed in solutions
containing the metallic ions U3+, V2+, and Y3+. The following observations were
recorded.
Trial
1
2
3
4
Ion
U3+
V2+
V2+
Y3+
Metal
Y
U
Y
V
Observation
reaction
reaction
reaction
no reaction
The oxidizing agents from the strongest to the weakest are
A.
V2+, U3+, Y3+
B.
U3+, V2+, Y3+
C.
Y3+, U3+, V2+
D.
V2+, Y3+, U3+
14.
Use the data below to answer the question.
Mo3+(aq) +
Ir(s)

no observable reaction
Ir3+(aq) +
Nd(s)

Nd3+(aq) + Ir(s)
3+
Mo (aq) +
Nd(s)

Nd3+(aq) + Mo(s)
From these data it can be predicted that the oxidizing agents, listed
to weakest, are:
A.
Ir3+
Mo3+ Nd3+
3+
B.
Mo
Nd3+
Ir3+
3+
3+
C.
Ir
Nd
Mo3+
D.
Mo
Ir
Nd
from strongest
29
15.
Which process could cause X2-(aq) to change to X+(aq)?
A.
B.
C.
D.
Z(s)
Z(s)
Z2-(aq)
Z3-(aq)




Z3-(aq)
Z3+(aq)
Z+(aq)
Z(s)
16.
In the reaction, what is the reducing agent?
4 Zn(s) + 10 H+(aq) + NO3-(aq)

NH4+(aq) + 4 Zn2+(aq) + 3 H2O(l)
A.
Zn(s)
B.
H+(aq)
C.
Zn2+(aq)
D.
NO3-(aq)
16.
A student observed the reactions between four different metals and the solutions
of their ions, and then recorded these 'spontaneous' reactions.
I.
W(s) + X+(aq)

W+(aq) + X(s)
+
II.
X(s) + Y (aq)

X+(aq) + Y(s)
+
III.
Y(s) + Z (aq)

Y+(aq) + Z(s)
+
IV.
X(s) + W (aq)

X+(aq) + W(s)
+
V.
X(s) + Z (aq)

X+(aq) + Z(s)
If equation I is correct, which equation did the student record incorrectly?
A.
II
B.
III
C.
IV
D.
V
17.
The reaction below proceeds spontaneously.
A2+(aq) + X(s)

A(s) + X2+(aq)
Elements A(s) and X(s) respectively, could be
A.
B.
C.
D.
Cr2+ and Co
Pb2+ and Cu
Co2+ and Cu
Ni2+ and Zn
18.
A piece of Sn(s) was placed in the following solutions:
I.
Cu(NO3)2(aq)
II.
Hg(NO3)2(aq)
III.
AgNO3(aq)
IV.
Fe(NO3)2(aq)
A spontaneous reaction will occur in all solutions except
A.
I
B.
II
C.
III
D.
IV
19.
Theoretically, a reducing agent can be described as a substance that
A.
loses electrons and becomes reduced.
B.
loses electrons and causes reduction.
C.
gains electrons and causes oxidation.
D.
gains electrons and becomes reduced.
30
20.
In the reaction
Cu(s) + 2Ag+(aq)  Cu2+(aq) + 2Ag(s)
A.
Cu(s) is reduced by the oxidizing agent.
B.
Ag+(aq) is the reducing agent and Cu(s) is reduced.
C.
Cu(s) is the reducing agent and Ag+(aq) is reduced.
D.
Cu(s) is the oxidizing agent and Ag+(aq) is oxidized.
21.
Which of the following reactions is non-spontaneous?
A.
I2(s)
+
Fe(s)

2I-(aq)
+
Fe2+(aq)
2+
2+
4+
B.
Ni (aq) +
Sn (aq) 
Ni(s)
+
Sn (aq)
C.
2Li(s)
+
2H2O(l) 
2Li+(aq) + 2 OH-(aq) + H2(g)
D.
2Cl2(g) + 2 H2O(l) 
4Cl-(aq) + O2(g) + 4H+(aq)
22.
Which of the following best describes the process of oxidation?
A.
the process in which oxygen is produced
B.
the process in which electrons are added
C.
the process in which the oxidation number decreases
D.
the process in which the oxidation number increases
23.
What is the oxidation number of N in the mercury (II) compound Hg(NH 3)2Cl2
A.
-6
B.
-4
C.
-3
D.
+2
24.
Which of the following combinations will react spontaneously under standard
conditions?
A.
Ag
+
Br2
B.
Ni
+
Co2+
C.
Zn
+
Mg2+
D.
Au
+
HNO3
25.
Identify the substance that is oxidized in the following equation:
Br2 + SO2(g) + K2SO4 + 2H2O  2H2SO4 + 2KBr
A.
Br2
B.
SO2
C.
H2O
D.
K2SO4
26.
What is the reducing agent in the following equation?
Fe2+ + 2I-  Fe(s) + I2(s)
A.
I2
B.
IC.
Fe2+
D.
Fe3+
27.
What is the oxidation number of C in the C3H5O2- ion ?
A.
-1/3
B.
-2/3
C.
-1
D.
-2
31
28.
Which of the following best describes what happens when lead solid is placed in a
1.0 M solution of Cu(NO3)2?
A.
The solution turns a darker blue.
B.
No changes are observed.
C.
Copper solid forms on the lead and the solution changes colour.
D.
The mass of lead solid increases and the solution does not change colour.
29.
Identify the reducing agent in the following equation:
Zn + 2MnO2 + H2O
A.
Zn
B.
H2O
C.
MnO2
D.
Zn(OH)2
30.
⇌ Zn(OH)2 + 2MnO(OH)
Consider the following equation: Co + SO42- + 4H+ ⇌
Which statement is correct?
A.
The sulphur is oxidized and the cobalt is reduced.
B.
The cobalt is oxidized and the sulphur is reduced.
C.
The hydrogen is reduced and the cobalt is oxidized.
D.
The hydrogen is reduced and the oxygen is oxidized.
Redox
Co2+ + H2SO3 + H2O
Quiz #2
1.
Which of the following pairs of ions will react spontaneously in a solution?
A.
Cu2+ and Fe2+
B.
Pb2+ and Sn2+
C.
Co2+ and Cr2+
D.
Mn2+ and Cr2+
2.
When NO2 reacts to form N2O4 the oxidation number of nitrogen
A.
increases by 2
B.
increases by 4
C.
increases by 8
D.
does not change
3.
Consider the following redox equation:
12H+(aq) + 2IO3-(aq) + 10Fe2+(aq) → 10Fe3+(aq) + I2(s) + 6H2O(l)
The reducing agent is
A.
I2
B.
H+
C.
Fe2+
D.
IO3-
4.
The oxidation number of nitrogen increases in
A.
B.
C.
D.
5.
NO3- → NO
N2O4 → NI3
NH3 → NH4+
NO2 → N2O5
Which of the following represents a balanced reduction half-reaction?
A.
VO2 + 2H+ + 2e- → V2+ + H2O
B.
VO2 + H2 → V2+ + H2O + le-
32
6.
C.
VO2 + 2H+ + le- → V2+ + H2O
D.
VO2 + 4H+ + 2e- → V2+ + 2H2O
Consider the following half reaction:
Sb2O3 + 6H+ + 6e- ⇄ 2Sb + 3H2O
The oxidation number of antimony in Sb2O3
A.
increases by 3
B.
increases by 6
C.
decreases by 3
D.
decreases by 6
7.
Consider the following unbalanced half-reaction
HClO2 ⇄ HClO
The balanced half-reaction would have
A.
1 electron on the left
B.
1 electron on the right
C.
2 electrons on the left
D.
2 electrons on the right
8.
The oxidation number of platinum in Pt(H2O)42+ is
A.
+2
B.
0
C.
+4
D.
+1/2
9.
Consider the following half-reaction :
BrO- → Br(basic)
The balanced equation for the half-reaction is
A.
BrO- + 2H+ + 2e- → Br- + H2O
B.
C.
D.
BrO- + 2H+ → Br- + H2O + 2eBrO- + H2O → Br- + 2OH- + 2eBrO- + H2O + 2e- → Br- + 2OH-
10.
Consider the following redox reaction:
2MnO4- + 5CH3CHO + 6H+ → 5CH3COOH + 2Mn2+ + 3H2O
The species that loses the electron is
A.
H2O
B.
MnO4C.
CH3CHO
D.
CH3COOH
11.
Hydrogen has an oxidation number of –1 in
A.
H2
B.
NaH
C.
H2O
D.
KOH
12.
Consider the following:
2NO3- + 4H+ + 2e- → N2O4 + 2H2O
This equation represents
A.
reduction
B.
oxidation
C.
neutralization
D.
decomposition
33
13.
Which of the following half-reactions is balanced?
A.
IO3- + 6H+ +5e- → I2 + 3H2O
B.
IO3- + 6H+ + 4e- →½ I2 + 3H2O
C.
IO3- + 6H+ → ½ I2 + 3H2O + 5eD.
IO3- + 6H+ + 5e- → ½ I2 + 3H2O
14.
Consider the following redox reaction:
Al + MnO4- + 2H2O →Al(OH)4- + MnO2
The chemical species being oxidized is
A.
Al
B.
MnO4C.
Al(OH)4D.
MnO2
15.
Consider the following redox reaction:
6H+ + 6I- + ClO3- → 3I2 + 3H2O + ClThe reducing agent is
A.
IB.
I2
C.
H+
D.
ClO3-
16.
Nitrogen has an oxidization number of zero in
A.
N2
B.
NO2
C.
NH3
D.
HNO3
17.
When MnO4- reacts to form Mn2+, the manganese in MnO4- is
A.
reduced as its oxidation number increases
B.
reduced as its oxidation number decreases
C.
oxidized as its oxidation number increases
D.
oxidized as its oxidation number decreases
18.
Consider the following reaction:
2HNO3 + 3H2S → 2NO + 3S + 4H2O
The nitrogen in HNO3 undergoes
A.
reduction
B.
oxidation
C.
electrolysis
D.
neutralization
19.
The oxidation number in carbon in CaC2O4 is
A.
+2
B.
+3
C.
+4
D.
+6
20.
Consider the following redox reaction:
2Cr3+(aq) + 3Cl2(aq) + 7H2O(l) → Cr2O72-(aq) + 6Cl-(aq) + 14H+(aq)
The species which loses electrons is
A.
Cl2
B.
Cr3+
34
21.
C.
H2O
D.
Cr2O72Which equation represents a redox reaction?
A.
Pb2+ + 2Cl- → PbCl2
B.
CaO + CO2 → CaCO3
C.
Mg + 2HCl → MgCl2 + H2
D.
HCl + NaOH → NaCl + H2O
22.
In a redox reaction, ClO- was converted to Cl- in a basic solution. The balanced
half-reaction for this process is
A.
ClO- + H2O + 2e- → Cl- + 2OHB.
ClO- + 2OH- → Cl- + 2e- + H2O
C.
ClO- + H2O → Cl- + 2e- + 2OHD.
ClO- + 2OH- + 2e- → Cl- + H2O
23.
Which of the following equations is not predicted to represent a redox reaction?
A.
2 H2O(l) + O2(g)  2 H2O2(l)
B.
2 Sn2+(aq)  Sn(s) + Sn4+(aq)
C.
Ag+(aq)
+
Cl-(aq)  AgCl(s)
D.
C2H4(g) + 3 O2(g)  2 CO2(g) + 2 H2O(g)
24.
The metal molybdenum, Mo, can react to produce MoO 2(s). The half reaction that explains the change in
oxidation state of molybdenum can be written
A.
Mo(s) + 2e→
Mo2+
2+
B.
Mo(s)
→
Mo + 2eC.
Mo4+ + 4e→
Mo(s)
D.
Mo(s)
→
Mo4+ + 4e-
25.
Which incomplete half-reaction is an oxidation?
A.
2H+
+ 12 O2(g)
→
H2O(l)
B.
Cr2O72- + 14H+ →
2 Cr3+ + 7 H2O(l)
C.
K+
→
K(s)
D.
2 I- →
I2(s)
26.
Which of these would react spontaneously with Co(s) but not with H2(g)?
A.
H2O(l)
B.
Ni2+(aq)
C.
Ca2+(aq)
D.
Br-(aq)
27.
The chemical that will reduce copper (II) ions and also oxidize metallic nickel is
aqueous
A.
iron (III) nitrate
B.
tin (II) sulfate
C.
iron (II) nitrate
D.
zinc sulfate
28.
F2(g) is a strong reducing agent F2(g) has a strong attraction for electrons. Based on this
information, one should determine that
A.
the statement and the explanation are true, and that the explanation is
correct for the statement.
B.
both the statement and the explanation are true, but the explanation is not
correct for the statement.
C.
the statement is true, but the explanation is false.
D.
the statement is false, but the explanation is true
35
29.
Solutions containing Fe2+(aq), Sn2+(aq) and Cr2+(aq) are mixed together. The reaction
most likely to occur is
A.
2Fe2+(aq) + 2 H2O(l)
 Fe(s) + O2(g) + 4H+(aq)
2+
2+
B.
Sn (aq) + 2Cr (aq)
 Sn(s) + 2 Cr3+(aq)
2+
2+
4+
C.
Sn (aq) + Cr (aq)  Sn (aq) + Cr(s)
D.
Sn2+(aq) + 2 Fe2+(aq)
 Sn(s) + 2 Fe3+(aq)
30.
Four reducing agents listed in order of decreasing strength are W, Z, Y and X. Four
statements about the reaction between the reducing agents and their respective oxidizing
agents are:
I.
W(s) + X2+(aq)

W2+(aq) + X(s)
2+
II.
Y(s) + X (aq)

Y2+(aq) + X(s)
2+
III.
W(s) + Z (aq)

no reaction
IV.
Y(s) + Z2+(aq)

Y2+(aq) + Z(s)
The statement(s) inconsistent with the correct order of reducing agents is (are)
A.
IV only
B.
III only
C.
I and II
D.
III and IV
Redox
1.
Quiz #3
Balancing Redox reactions- Acid & Base Cell Potentials
Consider the following overall reaction:
2Rh+ + Pb(s) → 2Rh(s) + Pb2+The E0 for the half-reaction Rh+ + e- ⇄
A.
-0.86 V
B.
-0.60 V
C.
+0.60 V
D.
+0.86 V
E0 = 0.73 V
Rh is
2.
Which of the following systems would be correct if the zinc half-cell would have been chosen as the
standard instead of the hydrogen half-cell?
A.
The reduction potentials of all the half-cells would remain unchanged
B.
The reduction potentials of all the half-cells would increase by 0.76 V
C.
The reduction potentials of all the half-cells would have positive values
D.
The reduction potentials of the hydrogen half-cell decrease by 0.76 V
3.
Three beakers contain 1.0 M CuCl2. A piece of metal is placed in each of the
beakers
BEAKER
1
2
3
Reactions occur in
A
beaker 2 only
B.
beakers 1, 2, and 3
C.
beakers 1 and 2 only
D.
beakers 1 and 3 only
SOLUTION
CuCl2
CuCl2
CuCl2
METAL
Zn
Ag
Ni
36
4.
Consider the following redox reaction:
3SO2 + 3H2O + ClO3- → 3SO42- + 6H+ + ClThe reduction half-reaction is
A.
ClO3- + 6H+ → Cl- + 3H2O + 6eB.
ClO3- + 6H+ + 6e- → Cl - + 3H2O
C.
SO2 + 2H2O → SO42- + 4H+ + 2eD.
SO2 + 2H2O + 2e- → SO42- + 4H+
5.
What two substances are produced when Cr and 1.0 M MnO 4- react in a basic solution?
A.
Mn2+ and Cr3+
B.
MnO2 and Cr3+
C.
Mn2+ and Cr2+
D.
MnO2 and CrO42-
6.
Bromine, Br2, will react spontaneously with
A.
IB.
I2
C.
ClD.
Cl2
7.
The substances H2O2, H3PO4 and H2SO3 in order of increasing strengths as
oxidizing agents are.
A
H2O2, H3PO4, H2SO3
B.
H2SO3, H3PO4, H2O2
C.
H3PO4, H2SO3 , H2O2
D.
H2O2,H2SO3 , H3PO4
8.
Consider the following overall equation for an electrochemical cell:
3Ag+ + Cr → Cr3+ + 3Ag
At standard conditions ,the initial cell voltage is
A.
+0.06 V
B.
+0.39 V
C.
+1.21 V
D.
+1.54
9.
A solution of 1.0 M Co(NO3)2 should be stored in a container made of
A.
tin
B.
zinc
C.
aluminum
D.
magnesium
10.
A strong oxidizing agent has a
A.
weak attraction for electrons
B.
strong attraction for electrons
C.
weak ability to become reduced
D.
strong ability to become oxidized
11.
The two species which react spontaneously in acidic solutions are
A.
IO3- and I2
B.
SO42- and S
C.
BrO3- and Br D.
AuCl4- and Au
37
12.
13.
Consider the following redox reaction:
Co2+(aq) + 2Ag(s) → 2Ag+(aq) + Co(s)
The reaction is
A.
spontaneous and Eo is positive.
B.
spontaneous and Eo is negative.
C.
non-spontaneous and Eo is positive.
D.
non-spontaneous and Eo is negative
Referring to the data booklet, which of the following can act as an oxidizing agent but not as a reducing
agent?
A.
Zn
B.
ClC.
Sn2+
D.
Fe3+
14.
Which equation represents a redox reaction?
A.
Pb2+ + 2Cl- → PbCl2
B.
CaO + CO2 → CaCO3
C.
Mg + 2HCl → MgCl2 + H2
D.
HCl + NaOH → NaCl + H2O
15.
In a redox reaction, ClO- was converted to Cl- in a basic solution. The balanced half-reaction for this
process is
A.
B.
C.
D.
ClO- + H2O + 2e- → Cl- + 2OHClO- + 2OH- → Cl- + 2e- + H2O
ClO- + H2O → Cl- + 2e- + 2OHClO- + 2OH- + 2e- → Cl- + H2O
16.
Which of the following gives the correct oxidation numbers for the nitrogen atoms in all three chemical
species?
N2
Li3N
NO2A.
0
-3
+3
B.
-3
-3
+3
C.
0
+3
-3
D.
-3
-3
-3
17.
The oxidation number of manganese changes as MnO4- is converted to MnO2. How many electrons are
gained or lost by the manganese during the change?
A.
1e- lost
B.
1e- gained
C.
3e- lost
D.
3e- gained
18.
Which of the solutions listed below should NOT be stored in a tin-plated container?
I NaNO3(aq)
II AgNO3(aq)
III SnBr2(aq)
IV Cl2(aq)
A.
I only
B.
II and IV
C.
II, III and IV
D.
II and III
19.
If fluorine gas is bubbled through NaI(aq),
A.
B.
Na+(aq) is reduced
I-(aq) is oxidized
38
C.
D.
20.
A high school laboratory's waste container is used to dispose of aqueous
solutions of sodium nitrate, potassium sulfate, hydrochloric acid, and tin (II)
chloride. The most likely net redox reaction predicted to occur inside the waste
container is represented by the equation:
A.
B.
C.
D.
21.
Sn2+(aq) + 2NO3-(aq) + 4H+(aq)  2NO(g) + 2H2O(l) + Sn4+(aq)
2 H+(aq) + 2K+(aq)  H2(g) + K(s)
SO42-(aq) + 4H+(aq) + 2 Cl-(aq)  H2SO3(aq) + H2O(l) + Cl2(g)
Cl2(g) + Sn2+(aq)  Cl-(aq) + Sn(s)
The net ionic equation for the reaction between aqueous solutions of tin (II)
bromide and iron (III) nitrate is
A.
B.
C.
D.
22.
F2(aq) is oxidized
I-(aq) is reduced
Sn2+(aq) + NO3-(aq)  NO2(g) + Sn4+(aq)
Sn2+(aq) + 2 Fe3+(aq)  Sn4+(aq) + 2 Fe2+(aq)
2Sn2+(aq) + Fe3+(aq)  2 Sn3+(aq) + Fe2+(aq)
Sn2+(aq) + 2NO3-(aq)  2NO2(g) + Sn4+(aq
Use the following unbalanced redox reaction to answer this question.
__O2(g) + ___H+(aq) + ___Ag(s)

__Ag+(aq) + ___H2O(l)
The coefficients for the balanced equation are
A.
1,4,4,4,2
B.
1,4,1,1,2
C.
1,2,1,1,1
D.
1,1,1,1,1
23.
A student mixes various combinations of the metals Pd, Cd and Ga with 1.0 M
solutions of their ions. The student then measures the voltages and puts them in
the table below.
1
Ga
Pd2+
+1.18 V
2
Ga
Cd2+
+0.16 V
3
Cd
Pd2+
What voltage is produced by reaction # 3?
A.
-1.34 V
B.
-1.02 V
C.
+1.02 V
D.
+1.34 V
24.
Which of the following is a correctly balanced reduction half-reaction?
A.
2HCN + 2e C2N2 + 2H+
B.
2Sb + 3H2O + 6e-  Sb2O3 + 6H+
C.
NO3- + 3H+ + 3e-  HNO2 + H2O
D.
Sb2O5 + 6H+ + 4e-  2Sb(OH)2+
+ H2O
25.
Which of the following combinations will react spontaneously under standard
conditions?
A.
Ag
+
Br2
B.
Ni
+
Co2+
C.
Zn
+
Mg2+
D.
Au
+
HNO3
39
26.
Which of the following best describes what happens when lead solid is placed in a
1.0 M solution of Cu(NO3)2?
A.
Bubbles form on the lead.
B.
No changes are observed.
C.
Copper solid forms on the lead and the solution changes colour.
D.
The mass of lead solid increases and the solution does not change colour.
27.
Consider the following unbalanced equation for a redox reaction in acidic
solution:
Br- + BrO3-  Br2
What is the equation for the balanced reduction half-reaction?
A.
2Br-  Br2 + 2eB.
2Br- + 2e-  Br2
C.
5e- + 6H+ + 2BrO3-  Br2 + 3H2O
D.
10e- + 12H+ + 2BrO3-  Br2 + 6H2O
28.
What reaction will occur when a solution containing 1.0 M MgSO4 and 1.0 M
CoCl2 is stored in a galvanized (Zn coated) bucket?
A.
Mg(s) + Cl2  MgCl2(s)
B.
Co2+ + SO42-  CoSO4(s)
C.
Co2+ + Zn(s)  Zn2+ + Co(s)
D.
Mg2+ + Zn(s)  Zn2+ + Mg(s)
29.
When the skeletal equation I-  IO3- is balanced in acidic solution, H2O, H+
and e- will appear. Which of the following are the correct balancing coefficients?
H2O
H+
eA.
B.
C.
D.
30.
3
3
3
6
3
6
6
12
2
6
5
10
Consider the following balanced redox equation in acidic solution:
5H2O + 2CoCl2 + OCl-  2Co(OH)3 + 5Cl- + 4H+
Which of the following describes the amounts and locations of OH - and H2O if
the equation is balanced in basic solution?
A.
1H2O on the left and no OHB.
1H2O on the left and 4OH- on the left
C.
5H2O on the left and 4OH- on the left
D.
1H2O on the left and 4OH- on the right
40
Redox
Quiz #4
Electrochemical Cells/Electrolytic Cells
voltmeter
1.0 M KNO3
Pb
Zn
1M Zn(NO3)2
1M Pb(NO3)2
1.
In the electrochemical call above, the electrons flow from
A.
zinc to lead and the mass of zinc increases
B.
zinc to lead and the mass of lead increases
C.
lead to zinc and the mass of zinc increases
D.
lead to zinc and the mass of lead increases
2.
The initial cell voltage is
A.
-0.89 V
B.
-0.63 V
C.
+0.63 V
D.
+0.89 V
3.
In an operating lead-zinc electrochemical cell shown above, the cathode
A.
gains mass as anions are reduced
B.
loses mass as anions are reduced
C.
gains mass as cations are reduced
D.
loses mass as cations are reduced
4.
The equation for the half-reaction at the anode is
A.
Zn2+ + 2e- → Zn
B.
Pb2+ + 2e- → Pb
C.
Zn → Zn2+ + 2eD.
Pb → Pb2+ + 2e-
5.
The equation for the half-reaction at the cathode is
A.
B.
C.
D.
6.
Zn2+ + 2e- → Zn
Pb2+ + 2e- → Pb
Zn → Zn2+ + 2ePb → Pb2+ + 2e-
The direction of electron flow in an electrochemical cell is from
A.
anode to cathode through the external wire
B.
cathode to anode through the external wire
C.
anode to cathode through the external wire and back through the salt bridge
D.
cathode to anode through the external wire and back through the salt bridge
41
7.
Which of the following is formed at the anode during the electrolysis of 1.0 M NaI?
A.
I2
B.
O2
C.
H2
D.
Na
Power Source
-
+
Pt
Pt
Molten MgCl2
8.
As this cell operates
A.
Cl- is oxidized at the anode
B.
Mg2+ is oxidized at the anode
C.
Cl- is oxidized at the cathode
D.
Mg2+ is oxidized at the cathode
9.
In an operating electrochemical cell, the anions migrate
A.
towards the anode through the wire
B.
towards the cathode through the wire
C.
towards the anode through the salt bridge
D.
towards thevoltmeter
cathode through the salt bridge
1.0 M KNO3
Cu
Mg
1 M Mg(NO3)2
1 M CuSO4
10.
As the above electrochemical cell operates
A.
nitrate ions migrate into the copper half-cell
B.
copper (II) ions migrate through the salt bridge
C.
magnesium ions migrate through the salt bridge
D.
potassium ions migrate into the magnesium half-cell
11.
In the above electrochemical cell, the reaction at the anode is
A.
Cu → Cu2+ + 2eB.
Cu2+ + 2e- → Cu
C.
Mg → Mg2+ + 2e-
42
D.
Mg2+ + 2e- → Mg
12.
In the above electrochemical cell, the initial voltage is
A.
2.03 V
B.
2.52 V
C.
2.71 V
D.
2.89 V
13.
Which of the following aqueous solutions produces H2(g) and O2(g) during electrolysis
A.
1.0 M KI
B.
1.0 M CuI2
C.
1.0 M K2SO4
D.
1.0 M CuSO4
14.
In the electrolysis of molten zinc chloride, the half-reaction at the anode is
A.
Cl2 + 2e- → 2ClB.
2Cl- → Cl2 + 2eC.
Zn2+ 2e- → Zn
D.
Zn → Zn2+ + 2evoltmeter
1.0 M KNO3
Ag
Ni
1 M Ni(NO3)2
1 M AgNO3
15.
The initial cell voltage at 25oC is
A.
-1.06 V
B.
-0.54 V
C.
+0.54 V
D.
+1.06 V
16.
The balanced equation for the overall reaction is
A.
Ni+(aq) + Ag(s) → Ag+(aq) + Ni(s)
B.
Ni(s) + Ag+(aq) → Ag(s) + Ni+(aq)
C.
Ni2+(aq) + 2Ag(s) → 2Ag+(aq) + Ni(s)
D.
Ni(s) + 2Ag+(aq) → 2Ag(s) + Ni2+(aq)
17.
This redox reaction occurs because
A.
Ag(s) is a stronger oxidizing agent than Ni(s)
B.
Ag(s) is a weaker reducing agent than Ni(s)
C.
Ag+(aq) is a stronger reducing agent than Ni2+(aq)
D.
Ag+(aq) is a weaker oxidizing agent than Ni2+(aq)
43
voltmeter
1.0 M KNO3
Pb
Au
1 M Au(NO3)3
1 M Pb(NO3)2
18.
The direction of the electron flow is
A.
from Au to Pb through the wire
B.
from Pb to Au from the wire
C.
from Au to Pb through the salt bridge
D.
from Pb to Au through the salt bridge
19.
As the cell operates
A.
NO3- and K+ will migrate toward the Pb half-cell
B.
NO3- and K+ will migrate toward the Au half-cell
C.
NO3- will migrate toward the Pb half-cell and K+ will migrate toward the Au half-cell
D.
NO3- will migrate toward the Au half-cell and K+ will migrate toward the Pb half-cell
20.
The initial voltage is
A.
-1.37 V
B.
0.00 V
C.
1.37 V
D.
1.63 V
21.
Which of the following is a balanced half-reaction in base?
A.
Cl2 + 3H2O → ClO3- + 6H+ + 5eB.
Cl2 + 6OH- → ClO3- + 5e- + 3H2O
C.
Cl2 + 6H2O → 2ClO3- + 12H+ + 10eD.
Cl2 + 12OH- → 2ClO3- + 6H2O + 10e-
22.
In which of the following unbalanced equations does chromium undergo oxidation?
A.
Cr3+ → Cr
B.
Cr3+ → Cr2+
C.
Cr3+ → Cr2O72D.
CrO42- → Cr2O72-
23.
Which of the following is formed at the anode and cathode during the electrolysis of
1.0 M Na2SO4?
Anode
Cathode
A.
O2
H2
B.
H2
O2
44
C.
H2
Na
D.
S
Na
Consider the electrolytic cell shown in the following diagram:
24.
Power Source
-
+
Pt
Cu
1 M AgNO3
Which of the following describes the anion movement and electrode masses for the above
cell?
Anion Movement
Mass of Pt Electrode
Mass of Cu Electrode
A.
to the Cu
increases
increases
B.
to the Cu
increases
decreases
C.
to the Pt
decreases
increases
D.
to the Pt
decreases
decreases
25.
Which of the following occurs when 1 M NiSO4 is electrolyzed using inert
carbon electrodes?
A.
The cathode dissolves.
B.
Hydrogen gas is produced.
C.
The pH of the solution decreases.
D.
The [Ni2+] increases.
26.
Which of the following describes electrolysis?
A.
a process that uses electrical energy to cause a spontaneous reaction
B.
a process that generates electrical energy using a spontaneous reaction
C.
a process that uses electrical energy to cause a non-spontaneous reaction
D.
a process that generates electrical energy using a non-spontaneous reaction
45
Power Source
-
+
Pt
Cu
1 M NiI2
27.
What products would form at the anode and cathode as this cell operates?
Anode
Cathode
A.
I2
Ni
B.
Ni
I2
C.
O2
H2
D.
Cu2+
Ni
28.
In the above cell, if 1.0 M NiI2 is replaced with molten NiI2, what products would form at the electrodes?
Anode
Cathode
A.
I2
Ni
B.
Ni
I2
C.
O2
H2
D.
Cu2+
Ni
voltmeter
1.0 M KNO3
Pt
Pt
1 M KMnO4
Acidified
29.
1 M H2SO3
In the above cell, which describes the movement of the electrons?
A.
They move from left to right towards the anode.
B.
They move from right to left towards the anode.
C.
They move from right to left towards the cathode.
D.
They move from left to right towards the cathode.
46
30.
Which of the following best describes what happens to the mass of the anode and the
mass of the cathode as the cell operates?
Anode Mass
Cathode Mass
A.
decreases
increases
B.
decreases
no change
C.
no change
decreases
D.
no change
no change
31.
What is the standard voltage E0 for the cell?
A.
0.43 V
B.
0.77 V
C.
1.34 V
D.
1.68 V
Quiz #5
Application of Cells
1.
The corrosion of iron can be prevented by attaching a piece of zinc to the iron because
the
A.
iron acts as an anode
B.
zinc reduces more readily than iron
C.
electrons flow from the zinc to the iron
D.
iron ions form more readily than zinc ions
2.
An iron spoon is electroplated with copper. The equation representing the reduction reaction is
A.
B.
C.
D.
3.
In an operating zinc-copper electrochemical cell, the oxidizing agent
A.
B.
C.
D.
4.
loses electrons at the anode
loses electrons to the cations
gains electrons at the cathode
gains electrons from the anions
An example of electro refining is the
A.
B.
C.
D.
5.
Cu2+(aq) + 2e- → Cu(s)
Cu(s) → Cu2+(aq) + 2eFe2+(aq) + 2e- → Fe(s)
Fe(s) → Fe2+(aq) + 2e-
extraction of aluminum from bauxite
purification of lead from an impure anode
recovery of zinc from a zinc sulphide solution
production of chlorine from a sodium chloride solution
Electroplating always involves the
A.
B.
C.
D.
oxidation of anions
reduction of cations
reduction at the anode
oxidation at the cathode
47
6.
Hydrogen and oxygen react to provide energy in a
A.
B.
C.
D.
ANODE
carbon
pure lead
pure lead
impure lead
A.
B.
C.
D.
8.
dry cell
fuel cell
alkaline cell
lead-acid storage cell
CATHODE
impure lead
carbon
impure lead
pure lead
7.
En electrolytic process is used to purify
impure lead. The electrodes are
In the cell below the half-reaction at the cathode is
Cu2+ + 2e- → Cu(s)
2SO42- → S2O82- + 2eH2O → ½ O2(g) + 2H+ + 2e2H2O + 2e- → H2(g) + 2OH-
A.
B.
C.
D.
Power Source
-
+
Iron Key
Pt
1.0 M CuSO4
9.
In the electrolysis of molten PbBr2, the products at the anode and cathode are
A.
B.
C.
D.
ANODE
(INERT)
Br2
O2
Pb
Br2
CATHODE
(INERT)
H2
Pb
Br2
Pb
48
10.
Under which conditions could an electrochemical cell provide 0.93V?
A.
B.
C.
D.
11.
water forming oxygen gas
water forming hydrogen gas
sea water forming chlorine gas
sea water forming bromine liquid
the nickel coin must be the cathode
the cathode must be made of copper
the electrons must flow to the anode
the solution must contain nickel ions
Ba2+
Al3+
Sn2+
Na+
The principal function of a fuel cell is to
A.
B.
C.
D.
16.
Pb
2eAg
e-
Which of the following ions can be reduced from an aqueous solution
A.
B.
C.
D.
15.
2e- →
Pb2+ +
e- →
Ag+ +
To plate a nickel coin with copper
A.
B.
C.
D.
14.
Pb2+ +
Pb →
Ag+ +
Ag →
An industrial process involving electrolysis is the reduction of
A.
B.
C.
D.
13.
Cathode
Mg
Cu
Pb
Ag
The reduction reaction in the above electrochemical cell is
A.
B.
C.
D.
12.
Anode
Cu
Mg
Ag
Pb
produce fuel
electrolyze fuel
produce hydrogen
produce electricity
If a piece of nickel is to be gold-plated using an electrolytic process, which half-reaction occurs at the
cathode?
A.
B.
C.
D.
Ni → Ni2+ + 2eNi2+ + 2e- → Ni
Au → Au3+ + 3eAu3+ + 3e- → Au
49
17.
Consider the following redox reaction
As2O3 + 2NO3- + 2H2O + 2H+ → 2H3AsO4 + N2O3
In this reaction, nitrogen
A.
loses electrons and increases in oxidation number
B.
gains electrons and increases in oxidation number
C.
loses electrons and decreases in oxidation number
D.
gains electrons and decreases in oxidation number
18.
In an electrochemical cell, the cathode
A.
is reduced
B.
loses mass
C.
is the reducing agent
D.
is the site of reduction
19.
When 1.0 M NaI is electrolyzed, bubbles of gas form on one electrode and a reddish-brown substance
forms on the other. The half-reaction at the cathode is
A.
2I- → I2 + 2eB.
Na+ + e- → Na
C.
H2O + ½ O2 + 2H+ + 2eD.
2H2O +2e- → H2 + 2OH-
Redox
Quiz #6
Corrosion & Cathodic Protection Titration
1.
Which of the following metals could be used to cathodically protect a sample of
lead?
A.
iron
B.
gold
C.
silver
D.
copper
2.
A piece of iron can be prevented from corroding by
A.
making it a cathode
B.
placing it in an acidic solution
C.
attaching a small piece of lead to it
D.
attaching a small piece of gold to it
3.
To determine the [Fe2+] in a solution of FeSO4 by e redox titration, a suitable
reagent would be an acidified solution of
A.
Cr3+
B.
Mn2+
C.
SO42D.
Cr2O72-
4.
As a metal corrodes,
A.
it gains electrons
B.
it becomes reduced
C.
it acts as a reducing agent
D.
its oxidation number decreases
5.
Which method will cathodically protect a piece of iron?
A.
Paint the iron
B.
Cover the iron with grease
C.
Attach a piece of lead tot he iron
50
D.
Attach a piece of magnesium to the iron
6.
Corrosion of iron can be prevented by attaching a piece of
A.
Mn
B.
Cu
C.
Pb
D.
Sn
7.
A student attempted to determine the Eo (volts) of the following half-reaction:
Pd2+ + 2e- → Pd Pd2+ reacts with Cu(s) but not with Hg(l).
Based on the above, the Eo (volts) of a Pd half-cell is
A.
less than 0.34 V
B.
greater than 1.50 V
C.
greater than 0.85 V but less than 1.50 V
D.
greater than 0.34 V but less than 0.85 V
8.
Consider the following redox equation:
Br2 + SO2 + Na2SO4 + 2H2O → 2H2SO4 + 2NaBr
Which of the following is gaining electrons?
A.
Br2
B.
SO2
C.
H2O
D.
Na2SO4
9.
The reaction that occurs when pieces of lead, zinc, copper and silver are placed in
a solution of Ni(NO3)2 is
A.
Pb + Ni2+ → Pb2+ + Ni
B.
Zn + Ni2+ → Zn2+ + Ni
C.
Cu + Ni2+ → Cu2+ + Ni
D.
2Ag + Ni2+ → 2Ag+ + Ni
voltmeter
1.0 M KNO3
Cu
Pb
1M Pb(NO3)2
1M Cu(NO3)2
10.
In the electrochemical cell above, the electrons flow from
A.
copper to lead through the wire
B.
lead to copper through the wire
C.
copper to lead through the salt bridge
D.
lead to copper through the salt bridge
11.
In the electrochemical cell above, the initial Eo value is
A.
0.03 V
B.
0.21 V
51
C.
D.
0.29 V
0.47 V
12.
A reaction that occurs during the corrosion of iron is
A.
Fe + 3e- → Fe3+
B.
Fe → Fe2+ + 2eC.
Fe2+ + 2e- → Fe
D.
Fe3+ + e- → Fe2+
13.
Consider the following reaction
Zn(s) + 2Ag+(aq) → Zn2+(aq) + 2Ag(s)
What volume of 0.500 M AgNO3 is required to react completely with 6.54 g of
zinc?
A.
0.0131 L
B.
0.0262 L
C.
0.200 L
D.
0.400 L
14.
Consider the following diagram:
Power Source
Cu
+
Fe
Porous Membrane
Why would this cell 1
failMtoCu(NO
electroplate
3)2 the Fe nail with copper?
A.
The Cu is inert.
B.
The Fe nail is the anode.
C.
The Fe nail is the cathode.
D.
The porous membrane prevents reaction.
52
15.
Consider the following diagram:
Power Source
+
-
Fe
Cu
Porous Membrane
1 M AgNO3
Why would this cell fail to electroplate the Fe nail with copper?
A.
The Cu is the cathode.
B.
The electrolyte does not contain Cu2+.
C.
The Fe nail is the cathode.
D.
The porous membrane prevents reaction.
16.
A 10.0 mL water sample was analyzed for [Fe2+] using a redox titration with
acidified KMnO4. The equation for the reaction is:
MnO4- + 5Fe2+ + +8H+  Mn2+ + 5Fe3+ + 4H2O
A 10.0 mL sample was titrated with 12.5 mL of 0.100 M KMnO4 solution.
What is the [Fe2+] in the water sample?
A.
0.025 M
B.
0.13 M
C.
0.28 M
D
0.63 M
17.
Why is aluminum a good choice for the manufacture of outdoor structures?
A.
Pure aluminum is easily reduced.
B.
Pure aluminum is not easily oxidized.
C.
Pure aluminum is easily reduced, but forms a protective coating.
D.
Pure aluminum is easily oxidized, but forms a protective coating.
18.
Which of the following are produced at the anode and the cathode during the
electrolysis of aqueous calcium iodide using carbon electrodes?
Anode
Cathode
A.
Iodine
Calcium
B.
Hydrogen
Oxygen
C.
Oxygen Hydrogen
D.
Iodine
Hydrogen
19.
Which of the following are produced at the anode and the cathode during the
electrolysis of molten calcium iodide using carbon electrodes?
Anode
Cathode
A.
Iodine
Calcium
B.
Hydrogen
Oxygen
C.
Oxygen Hydrogen
D.
Iodine
Hydrogen
53
20.
Which of the following are produced at the anode and the cathode during the
electrolysis of aqueous potassium fluoride using carbon electrodes?
Anode
Cathode
A.
Oxygen Potassium
B.
Hydrogen
Oxygen
C.
Oxygen Hydrogen
D.
Fluorine Potassium
21.
Which of the following are produced at the anode and the cathode during the
electrolysis of molten potassium fluoride using carbon electrodes?
Anode
Cathode
A.
Oxygen
Potassium
B.
Hydrogen
Oxygen
C.
Oxygen
Hydrogen
D.
Fluorine
Potassium
22.
Two reactions involved in the refining of copper are:
Reaction I
2Cu2S + 3O2  2Cu2O + 2SO2
Reaction II
Cu2S
+ 2Cu2O  6Cu + SO2
What happens to the copper ions in this process?
A.
They are reduced in Reaction I.
B.
They are reduced in Reaction II.
C.
They are oxidized in Reaction I.
D.
They are oxidized in Reaction II.
23.
Identify the oxidation number for manganese in MnO4-.
A.
-7
B.
7
C.
8
D.
9
24.
Which of the following is more difficult to reduce than the H+ ion?
A.
I2
B.
Ag+
C.
Zn2+
D.
Cu2+
25.
The equation for the decomposition of nitrous acid is
3HNO2  2NO + HNO3 + H2O
Which of the following is correct?
A.
This is a redox reaction.
B.
This is an acid-base reaction.
C.
This is a reduction half equation.
D.
This is an oxidation half equation.
26.
An equation for the rusting of iron is shown below:
4Fe
+ 3O2  2Fe2O3
Which of the following is false?
A.
This is a redox reaction.
B.
O2 is the oxidizing agent.
C.
Metallic iron is reduced to Fe3+.
D.
Metallic iron is the reducing agent.
54
27.
In which of the following chemical changes will there be an oxidation number
change of +3 ?
A.
Cr3+  Cr2+
B.
ClO-  ClO2C.
Cr3+  Cr2O72D.
Mn2+  MnO4-
28.
Consider the following spontaneous reactions:
Cd2+
+
Np

Cd
+
Cd
+
Pd2+

Pd
+
Np3+
+
Ce

Np
+
Which is the strongest oxidizing agent?
A.
Cd2+
B.
Ce3+
C.
Np3+
D.
Pd2+
29.
30.
Np3+
Cd2+
Ce3+
Consider the following equation:
H3AsO4 + 4Zn + 8H+ AsH3 + 4Zn2+
Which of the following is correct?
A.
Oxygen is reduced.
B.
Arsenic is reduced.
C.
Zinc is the oxidizing agent.
D.
The reaction is not a redox reaction.
+ 4H2O
What is the oxidation number of iron in magnetite, Fe3O4 ?
A.
+4/3
B.
+2
C.
+8/3
D.
+3
Redox Web Review
1)
Which most readily gains electrons?
Cu
2)
Cu2+
Fe2+2
Zn2+
Au3+
Which most readily loses electrons?
Hg(l)
Cu2+
Sn4+
Ba
Al
Calculate the cell potentials or voltages (E0) Indicate spontaneity.
3.
Cl2 + 2Br- → 2Cl- +Br2
55
→
4.
2MnO4- + 5Pb +16H+
5.
Will AgNO3 react with Zn? Write a balanced redox reaction and calculate Eo
6.
What would happen if you used an iron spoon to stir a solution of Al2(SO4)3(aq) ?
Write a balanced redox reaction and calculate Eo.
7.
What are the differences between an electrochemical cell and an electrolytic cell?
Electrochemical cell
8.
2Mn2+ + 8H2O + 5Pb2+
Electrolytic cell
What are the similarities between an electrochemical cell and an electrolytic cell?
Electrochemical cell or Electrolytic cell
56
9.
State how you would determine each of the following in an electrochemical or
electrolytic cell.
Electrochemical Cell
Electrolytic Cell
The site of reduction
The site of oxidation
The +ve electrode
The -ve electrode
The anions migrate to the
The cations migrate to the
The electrode that gains mass
The electrode that loses mass
The electrons flow from
10.
Draw an operating electrochemical cell using an Al half-cell and a Mg half-cell. Label
the parts of the electrochemical cell including the anode or cathode, and all reagents and
materials used. Write the reactions and determine the E0.
11.
Write the half reaction that occurs at each electrode during the electrolysis of aqueous
1.0 M NaI.
Anode :
Cathode :
What is the minimum required voltage for this process?
12.
Write the half reaction that occurs at each electrode during the electrolysis of molten NaI.
Anode :
Cathode :
What is the minimum required voltage for this process?
57
13.
Aluminum is produced industrially from aluminum oxide, Al2O3. Demonstrate your
understanding of this process by
(i) Describing how the process is carried out,
(ii) Writing equations of the reactions involved in the process, and
(iii) Describing how the problem of the high melting point ofAl2O3 is overcome.
14.
Consider the following redox data:
3V + 2Ga3+ → 3V2+ + 2Ga
Eo = +0.64 V
3V2+ + 2Al
Eo = +0.46 V
→ 3V + 2Al3+
Based on these observations, a student concludes that Ga+3 and Al will react
spontaneously. List the oxidizing agents in order of decreasing strength. Write reduction
reactions for each. Determine the strongest reducing agent. Determine if Ga+3 and Al will
react spontaneously.
15.
Balance the equation for the following half reaction occurring in acid solution:
V(s)
16.
→
HV2O73-
Balance the following redox reaction occurring in basic solution:
MnO4-
+
C2O42- →
MnO2
+
CO2
58
17.
250.0 ml 0.200M MnO4- reacts with excess SO32-. How many grams of MnO2 are
produced?
2MnO4- + 3SO32- +H2O → 2MnO2 +3SO42- + 2OH-
18.
Determine the oxidation number for each bold atom.
MnO2
IO3-
Cr2O72-
C2O42-
HOOH
NO3-
H3PO4
Na2C2O4
19.
Al(NO3)3 NH4Cl
I2
N2O3
NaH
Pt(H2O)42+
250.0 mL of 0.500M MnO4- are required to titrate a 100.0 ml sample of SO3-2. Calculate
the [SO3-2]
2MnO4- + 3SO32- +H2O → 2MnO2 + 3SO42-+ 2OH-
20.
How is the breathalyzer reaction used to determine BAC? Write the reaction and describe
how it works.
59
21.
2H+
+
Mg
→
Mg2+ +
H2
Determine the Oxidizing agent__________ and the Reducing agent_________
22.
Choose a suitable redox reactant to oxidize Cl- toClO4- in a redox titration.
23.
Describe as an electrochemical or electrolytic cell:
a) Fuel cell
b) Charging a car battery
c) Discharging a car battery
d) Ni plating
e) Industrial Al production
f) Cl2 production
g) Electrowinning
24)
Which of the reactants is gaining electrons? Which of the reactants is the oxidizing
agent?
Br2 + SO2 + Na2SO4 + H2O → 2H2SO4 + 2NaBr
25)
A student studied the following reactions and she recorded:
Pd2+ + Cu → Pd + Cu2+ spontaneous
Pd2+ + Au → no reaction
Pd2+ + Hg → no reaction
Au3+ + Hg → Au + Hg2+ spontaneous
60
List the oxidizing agents from strongest to weakest. List the reducing agents from
strongest to weakest.
Predict if the reaction will occur.
Au3+
26)
+
Cu
→
Match each type of electrolytic cell with the example cell.
Electrowinning A silver anode oxidizes & Ag reduces on a Cu cathode
Electroplating Pure Pb is reduced at the cathode while impure Pb oxidizes at the anode
Electrorefining Pure Al is reduced at the cathode from molten bauxite (Al2O3).
27.
Which of the above cells requires continuous input of O2 and H2 and is produced by
Ballard Industries.
28.
List the anode, cathode, anode reaction, cathode reaction, and electrolyte for each
commercial electrolytic cell.
Cell
Electrolysis of
Molten Al2O3
Electrolysis of
Aqueous NaCl
Silver-plating
a Cu plating
Electrorefining
pure Pb from
impure Pb
anode anode reaction
cathode cathode reaction
electrolyte
61
29.
Describe each term:
salt bridge
electrolyte
anode
cathode
spontaneous
electron affinity
cation
anion
electrochemical
cell
electrolytic cell
oxidation number
electrolysis
oxidation
reduction
oxidizing agent
reducing agent
electrode
corrosion
electrowinning
electrorefining
over potential
effect
fuel cell
30.
Define corrosion of a metal, and illustrate your definition with reference to an example,
using appropriate equations. Give TWO methods by which corrosion can be prevented
and describe how each method works. The two methods must involve different chemical
principles.
31.
Which you would choose Zn or Cu to cathodically protect iron?
62
32.
A2+ does not react with B, while C2+ reacts with B. Rank the oxidizing agents in
decreasing order of strength. Rank the reducing agents in decreasing order of strength.
Will A2+ react with C?
33.
Completely analyze the following electrochemical cell.
voltmeter
1.0 M KNO3
Cu
Zn
1 M Zn(NO3)2
1 M Cu(NO3)2
The anode reaction is:
The cathode reaction is:
The electrons flow from ___ to ___
The ions that migrate to the Zn electrode are:
The ions that migrate to the Cu electrode are:
The initial voltage of this cell is:
The voltage of this cell once equilibrium is reached is:
Describe the change in [Cu+2] in the Cu half cell
Describe the change in [NO3-1] in the Zn half cell
63
34.
Completely analyze the following electrochemical cell.
voltmeter
1.0 M KNO3
H2(g)
Cu
Pt
1 M HCl
1 M Cu(NO3)2
The anode reaction is:
The cathode reaction is:
The electrons flow from ___ to ___
The ions that migrate to the Pt electrode are:
The ions that migrate to the Cu electrode are:
The intial voltage of this cell is:
The voltage of this cell once equilibrium is reached is:
Describe the change in [Cu+2] in the Cu half cell
Describe the change in [NO3-1] in the H+/H2 half cell
64
35.
Completely analyze the following electrolytic cell.
Power Source
-
+
C
C
Molten Al2O3
Anode Reaction
Cathode Reaction
Chemicals produced at the anode
Chemicals produced at the cathode
The electrons flow from __to __
The chemical used to lower the mp is:
Which electrode is the anode ?
65
36.
Completely analyze the following electrolytic cell. Note that the electrodes are not inert
and because of that, the anode might oxidize.
Power Source
Cu
Cu
1 M NaF
Anode Reaction
Cathode Reaction
Chemicals produced at the anode
Chemicals produced at the cathode
The electrons flow from
The MTV
Which electrode is the anode ?
+
66
Electrochemistry Practice Test # 1
1.
The following represents the process used to produce iron from iron III oxide:
Fe2O3 + 3CO → 2Fe + 3CO2 What is the reducing agent in this process?
A.
Fe
B.
CO
C.
CO2
D.
Fe2O3
2.
Consider the following reaction: 2HNO2 + 2I- + 2H+ → 2NO + I2 +2H2O
The oxidation number for each nitrogen atom
A.
increases by 1
B.
increases by 2
C.
decreases by 1
D.
decreases by 2
3.
Which of the following reactions is spontaneous?
A.
2I- + Ag → Ag+ + I2
B.
Co2+ + Cu → Co + Cu2+
C.
Cu2+ + Pb → Pb2+ + Cu
D.
Ni2+ + 2Ag → 2Ag+ + Ni
4.
Consider the following redox reaction for a lead-acid storage cell:
Pb + PbO2 + 4H+ + 2SO42- → 2PbSO4 + 2H2O
The balanced, reduction half reaction is
A.
Pb + SO42- → 2PbSO4 + 2eB.
Pb + 2H+ + SO42- → PbSO4 + 2H2O + 2eC.
PbO2 + 4H+ + SO42- + 2e- → PbSO4 + 2H2O
D.
PbO2 + 2SO42 + 2H2O + 2e- → PbSO4 + 2OH-
5.
Consider the following reaction: Cd2+(aq) + Zn(s) → Cd(s) Zn2+(aq)
The potential for the reaction is +0.36 V. What is the reduction potential for the cadmium ion?
A.
-1.12 V
B.
-0.40 V
C.
+0.40 V
D.
+1.12 V
6.
Which of the following involves a nonspontaneous redox reaction?
A.
fuel cell
B.
electroplating
C.
redox titration
D.
carbon dry cell
7.
Consider the following redox reaction:
2MnO4- + 16H+ + 5Sn2+ → 2Mn2+ + 8H2O + 5Sn4+
In a redox titration, 0.60 mole of KMnO4 reacts completely with a solution of Sn(NO3)2. How many moles
of Sn(NO3)2 were present in the solution?
A.
0.024 moles
B.
0.060 moles
C.
1.5 moles
D.
0.30 moles
67
8.
Which of the following is not a redox reaction?
A.
Cu + Br2 → CuBr2
B.
CO + H2O → CO2 + H2
C.
CH4 + H2O → CO2 + 2H2O
D.
NaOH + HCl → NaCl + H2O
9.
What is the minimum voltage required to form nickel from an aqueous solution of NiI 2 using inert
electrodes?
A.
0.26 V
B.
0.28 V
C.
0.54 V
D.
0.80 V
10.
What substances are formed at the anode and cathode during electrolysis of molten sodium chloride?
Anode
Cathode
A.
O2
H2
B.
Na
Cl2
C.
Cl2
H2
D.
Cl2
Na
11.
A solution containing an unknown cation reacts spontaneously with both zinc and copper. The unknown
cation is
A.
1.0 M H+
B.
1.0 M Ag+
C.
1.0 M Sr2+
D.
1.0 M Mn2+
12.
Which of the following half-reactions are balanced?
A.
ClO- + H2O + e- → Cl2 + 2OHB.
2ClO- + H2O + 2e- → Cl2 + 3OHC.
2ClO- + 2H2O + 2e- → Cl2 + 4OHD.
2ClO- + 2H2O → Cl2 + 4OH- + 2e-
13.
Which of the following is a spontaneous redox reaction?
A.
Ag+ + I- → AgI
B.
Ag+ + Fe2+ → Ag + Fe3+
C.
3Ag+ + Au → 3Ag + Au3+
D.
2Ag+ + Ni2+ → 2Ag + Ni
14.
Salting the roads during the winter increases the amount of corrosion of cars. The is because the salt
A.
reacts with the iron
B.
provides an electrolyte
C.
acts as a reducing agent
D.
acts as an oxidizing agent
68
Consider the following electrochemical cell for the next five questions.
voltmeter
1.0 M KCl
Cu
u
Ni
1M Cu(NO3)2
1M Ni(NO3)2
15.
The half-reaction that occurs at the anode is
A.
Ni → N2+ + 2eB.
Ni2+ + 2e- → Ni
C.
Cu → Cu2+ + 2eD.
Cu2+ + 2e- → Cu
16.
The half-reaction that occurs at the cathode is
A.
Ni → N2+ + 2eB.
Ni2+ + 2e- → Ni
C.
Cu → Cu2+ + 2eD.
Cu2+ + 2e- → Cu
17.
The cell potential or Eo is
A.
0.41 V
B.
0.78 V
C.
0.34 V
D.
0.60 V
18.
The following ions migrate to the Cu electrode
A.
K+
Cu2+
Ni2+
2+
2+
B.
Cu
Ni
C.
ClNO3D.
Cl
NO32e-
19.
The electrons flow
A.
through the salt bridge from Cu to Ni
B.
through the salt bridge from Cu to Ni
C.
through the wire from Cu to Ni
D.
through the wire from Ni to Cu
20.
Which of the following will not react spontaneously with 1.0 M HCl?
A.
tin
B.
lithium
C.
mercury
D.
magnesium
69
21.
Which of the following can be produced by electrolysis from a 1.0 M aqueous solution containing its ion?
A.
nickel
B.
sodium
C.
aluminum
D.
magnesium
22.
In order for an electrolytic cell to operate, it must have
A.
a voltmeter.
B.
a salt bridge.
C.
a power supply.
D.
an aqueous solution.
23.
In the electrolysis of molten ZnCl2 using carbon electrodes, the reaction that occurs at the anode is
A.
Zn → Zn2+ + 2eB.
Zn2+ + 2e- → Zn
C.
2Cl- → Cl2 + 2eD.
Cl2 + 2e- → 2Cl-
24.
In the electrolysis of molten zinc chloride, the half-reaction at the anode is
A.
Cl2 + 2e- → 2ClB.
2Cl- → Cl2 + 2eC.
Zn2+ + 2e- → Zn
D.
Zn → Zn2+ + 2e-
25.
The corrosion of iron can be prevented by attaching a piece of
A.
Mn
B.
Cu
C.
Pb
D.
Sn
26.
The oxidation number of carbon in CaC2O4 is
A.
+2
B.
+3
C.
+4
D.
+6
27.
To plate a nickel coin with copper,
A.
the nickel coin must be the cathode.
B.
the cathode must be made out of copper
C.
the electrons must flow to the anode
D.
the solution must contain nickel ions
Consider the following electrochemical cell for the next five questions.
voltmeter
1.0 M KNO3
Cu
Zn
uu
1M Cu(NO3)2
1M Zn(NO3)2
70
28.
Which of the following statements apply to this electrochemical cell?
I
Electrons flow through the wire toward the copper electrode.
II
The copper electrode increases in mass.
III
Anions move toward the Zn half-cell.
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II, and III
29.
The balanced equation for the overall reaction is
A.
Zn + Cu2+ → Cu + Zn2+
B.
Cu + Zn2+ → Zn + Cu2+
C.
Zn2+ + Cu → Cu2+ + Zn
D.
Cu + Zn → Zn + Cu
30.
At equilibrium the voltage of the above cell is
A.
-1.10 V
B.
0.00 V
C.
+0.42 V
D.
+1.10 V
31.
This redox reaction occurs because
A.
Zn is a stronger oxidizing agent than Cu
B.
Zn is a stronger reducing agent than Cu,
C.
Cu is a stronger oxidizing agent than Zn
D.
Zn2+ is a weaker reducing agent than Cu2+
32.
The initial cell voltage at 25 oC is
A.
-1.10 V
B.
+1.10 V
C.
+0.91 V
D.
+0.86 V
33.
Consider the following redox reaction: Co2+(aq) + 2Ag(s) ⇋ 2Ag+(aq) + Co(s)
The reaction is
A.
spontaneous and Eo is positive
B.
spontaneous and Eo is negative
C.
non-spontaneous and Eo is positive
D.
non-spontaneous and Eo is negative
34.
When MnO4- reacts to form Mn2+, the manganese in MnO4- is
A.
reduced as its oxidation number increases
B.
reduced as its oxidation number decreases
C.
oxidized as its oxidation number increases
D.
oxidized as its oxidation number decreases
35.
The electrolyte used in the alkaline battery is
A.
B.
C.
D.
KCl
NaOH
H2SO4
KOH
71
36.
The electrolyte used in an automobile battery is
A.
KCl
B.
NaOH
C.
H2SO4
D.
KOH
37.
The anode used in the commercial production of Aluminum is
A.
C
B.
Pt
C.
Al
D.
Al2O3
38.
The anode and cathode used in the electrorefining of impure lead to pure lead are
Anode
Cathode
A.
Pure Pb
Impure Pb
B.
Impure Pb
Pure Pb
C.
Pb2+
Pb
D.
Pb
Pb2+
39.
The anode in the LeClanche or common dry cell is
A.
C
B.
Zn
C.
Mg
D.
KOH
40.
Which of the following are electrolytic cells
I
II
III
IV
Electro winning
Electroplating
Charging a car battery
Fuel cell
A.
B.
C.
D.
I and II only
I, II, and III only
II and II only
I, II, III, and IV
Subjective
1.
Balance the following in basic solution.
MnO4-
+
C2O42-
→
MnO2
+
CO2
(basic)
72
2.
3.
Consider the electrolysis of 1.0 M H2SO4 using platinum electrodes.
a)
Write the oxidation half-reaction
b)
Write the reduction half-reaction
c)
Write the overall reaction and determine the minimum theoretical voltage required.
Consider the following diagram for the electro refining of lead.
Power Source
Pure Pb
Impure Pb
a)
On the diagram, label the anode and cathode.
b)
Write the formula for a suitable electrolyte
c)
Write the equation for the reduction half-reaction.
4.
Describe two chemically different methods that can be used to prevent corrosion of iron and explain why
each method works.
Method 1:
Explanation:
Method 2:
Explanation:
73
5.
The data below were obtained in a redox titration of a 25.00 mL sample containing Sn 2+ ions using 0.125 M
KMnO4 according to the following reaction: 2MnO4- + 16H+ + 5Sn2+ → 2Mn2+ + 8H2O + 5Sn4+
Calculate the [Sn2+]
Volume of KMnO4 used (mL)
Trial 1
Trial 2
Trial 3
Initial burette reading
2.00
13.80
24.55
Final burette reading
13.80
24.55
35.32
6.
A student wanted to electroplate a coin with copper.
7.
8.
a)
Identify a suitable anode
b)
Identify an appropriate electrolyte
c)
To with battery terminal (positive or negative) should the coin be connected?
Consider the electrolysis of molten magnesium chloride with Cu electrodes (Cu electrodes are not inert
and can oxidize: Cl-, or Cu will oxidize)
a)
Identify the product at the anode
b)
Write the equation for the reduction half-reaction.
c)
Write the equation for the overall reaction.
Completely analyze the following electrochemical cell.
voltmeter
1.0 M KNO3
Mn
Sn
nn
n
1M Sn(NO3)2
1M MnNO3)2
74
Chemistry 12
Electrochemistry Practice Test 2
voltmeter
1.0 M KCl
Ni
Pd
1M Pd(NO3)2
1.
As the cell operates, the electrons flow from the nickel electrode to the palladium electrode. The reaction
occurring at the anode is
A
B
C
D
2.
both the K+ and the NO3- migrate into the nickel half-cell
both the K+ and the NO3- migrate into the palladium half-cell
the K+ migrates into the nickel half-cell and the NO3- migrates into the palladium half-cell
the K+ migrates into the palladium half-cell and the NO3- migrates into the nickel half-cell
The initial cell voltage is 1.21 V. The reduction potential of Pd2+ is
A
B
C
D
4.
Pd → Pd2+ + 2eNi → Ni2+ + 2ePd2+ + 2e- → Pb
Ni2+ + 2e- → Ni
As the cell operates,
A
B
C
D
3.
1M Ni(NO3)2
-1.21 V
-.95 V
+0.95
+1.21 V
What substances are formed at the anode and cathode during electrolysis of molten sodium chloride,
NaCl(l)?
A
B
C
D
Anode
Cathode
O2
Na
Cl2
Cl2
H2
Cl2
H2
Na
75
5.
Consider the following electrolytic cell:
Power Source
+
-
Inert
Electrode
Inert
Electrode
Molten NaI(l)
In the cell above
A
B
C
D
6.
I- migrates to the anode and gains electrons
I- migrates to the cathode and loses electrons
Na+ migrates to the anode and loses electrons
Na+ migrates to the cathode and gains electrons
Which of the following are necessary for electroplating to occur using an electrolytic cell?
I
Two electrodes
II
A metal being reduced
III
A direct current power supply
A
B
C
D
I and II only
I and III only
II and III only
I, II, and III
7.
A fuel cell consumes H2 and O2 gas, uses a KOH electrolyte, and produces electricity. The reaction at the
anode is
A
2H+ + 2e- → H2
B
1/2O2 + 2H+ + 2e- → H2O
C
4OH- → O2 + 2H2O + 4eD
H2 + 2OH- → 2H2O + 2e-
8.
A student investigating redox reactions recorded the following results:
V2+ + Te2- → no reaction
U4+ + Te2- → U3+ + Te
Based on these results, the strengths of the oxidizing agents, arranged from
A
B
C
D
9.
V2+
U4+
U3+
V2+
Te
Te
Te2Te2-
strongest to weakest, are
U4+
V2+
V2+
U3+
What is the minimum voltage required to form nickel from 1 M NiI2 using inert electrodes?
A
0.26 V
B
0.28 V
C
0.54 V
D
0.80 V
76
10.
voltmeter
1.0 M KNO3
Ni
Zn
1M Zn(NO3)2
1M Ni(NO3)2
Which of the following occurs as the cell operates?
A
the Zn electrode is reduced and increases in mass
B
the Zn electrode is reduced and decreases in mass
C
the Zn electrode is oxidized and increases in mass
D
the Zn electrode is oxidized and decreases in mass
11.
Which of the following reactants would produce an E 0 of +0.63 V?
A
Ag+ + I2
B
Pb2+ + Zn
C
Mg2+ + Ca
D
Zn2+ + Mn
12.
The concentration of Fe2+(aq) can be determined by a redox titration using
A
KBr
B
SnCl2
C
KMnO4 (basic)
D
KBrO3 (acidic)
13.
Which of the following will oxidize Fe2+?
A
I2(s)
B
Ni(s)
C
Zn(s)
D
Br2(l)
14.
The oxidation number of carbon in C2O42- is
A
B
C
D
15.
+3
+4
+5
+6
Consider the following reaction: 3As2O3 + 4NO3- + 7H2O → 6H3AsO4 + 4NO
The oxidizing agent is
A
H+
B
H2O
C
NO3D
AsO3
77
16.
When W2O5 is converted to WO2 in a redox reaction, the W has been
A
reduced since its oxidation number has increased
B
reduced since its oxidation number has decreased
C
oxidized since its oxidation number has increased
D
oxidized since its oxidation number has decreased
17.
Consider the following:
I
Water
II
Oxygen gas
III
Nitrogen
At 25oC, a piece of iron rusts in the presence of
A
I only
B
III only
C
I and II only
D
II and III only
18.
Which of the following represents a redox reaction?
A
H2CO3 → H2O + CO2
B
CuS + H2 → H2S + Cu
C
AgNO3 + NaCl → AgCl + NaNO3
D
2HCl + Na2SO3 → 2NaCl + H2SO3
19.
The following reaction occurs in an electrochemical cell:
3Cu2+ + Cr → 2Cr3+ + 3Cu
The Eo for the cell is
A
0.40 V
B
0.75 V
C
1.08 V
D
2.50 V
20.
During the corrosion of magnesium, the anode reaction is
A
Mg → Mg2+ + 2eB
Mg2+ + 2e- → Mg
C
4OH- → O2 + 2H2O + 4eD
O2 + 2H2O + 4e- → 4OH-
21.
A molten binary salt, ZnCl2, undergoes electrolysis. The cathode reaction is
A
Zn → Zn2+ + 2eB
2Cl- → Cl2 + 2eC
Cl2 + 2e- → 2ClD
Zn2+ + 2e- → Zn
22.
Which of the following represents a redox reaction?
A
CaCO3 → CaO + CO2
B
SiCl4 + 2Mg → Si + 2MgCl2
C
2NaOH + H2SO4 → 2H2O + Na2SO4
D
AgBr + 2S2O32- → Ag(S2O3)23- + Br-
23.
The process of applying an electric current through a cell to produce a chemical change is called
A
corrosion
B
ionization
C
hydrolysis
D
electrolysis
78
24.
A student investigating redox reactions recorded the following results:
V2+ + Te2- → no reaction
U4+ + Te2- → U3+ + Te
Based on these results, the strengths of the oxidizing agents, arranged from strongest to weakest, are
A
V2+
Te
U4+
4+
B
U
Te
V2+
3+
2C
U
Te
V2+
2+
2D
V
Te
U3+
25.
A spontaneous redox reaction occurs when Sn2+ is mixed with
A
I2
B
Cu
C
H2S
D
Ag2S
26.
Consider the redox reaction:
2BrO3- + 10Cl- + 12H+ → Br2 + 5Cl2 + 6H2O
the oxidation half-reaction ivolved in this reaction is
A
2Cl- → Cl2 + 2eB
2H+ → H2 + 2eC
BrO3- + 6H+ + 5e- → ½ Br2 + 3H2O
D
BrO3- + 6H+ → ½ Br2 + 3H2O + 5e-
27.
Which of the following is not a redox reaction?
A
Cu + Br2 → CuBr2
B
CO + H2O → CO2 + H2
C
CH4 + O2 → CO2 + 2H2O
D
NaOH + HCl → NaCl + H2O
28.
During the electrolysis of 1.0 M Na2SO4, the reaction at the cathode is
A
Na+ + 1e- → Na
B
2SO42- → S2O82- + 2eC
2H2O → O2 + H+ + 4eD
2H2O + 2e- → H2 + 2OH-
29.
An oxidizing agent will cause which of the following changes?
A
PtO2 → PtO
B
PtO3 → PtO2
C
Pt(OH)2 → Pt
D
Pt(OH)22+ → PtO3
30.
Consider the overall reaction of the nickel-cadmium battery:
NiO2(s) + Cd(s) + 2H2O(l) → Ni(OH)2(s) + Cd(OH)2(s)
Which of the following occurs at the anode as the reaction proceeds?
A
B
C
D
31.
Cd loses 2e- and forms Cd(OH)2(s)
Cd gains 2e- and forms Cd(OH)2(s)
NiO2 loses 2e- and forms Ni(OH)2(s)
NiO2 gains 2e- and forms Ni(OH)2(s)
Which of the following can be produced by the electrolysis from a 1.0 M aqueous solution containing its
ions?
A
nickel
B
sodium
C
aluminum
D
magnesium
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32.
In the electrolysis of molten ZnCl2 using carbon electrodes, the reaction that occurs at the anode is
A
Zn → Zn2+ + 2eB
Zn2+ + 2e- → Zn
C
2Cl- → Cl2 + 2eD
Cl2 + 2e- → 2Cl-
33.
In order for the electrolytic cell to operate, it must have
A
a voltmeter
B
a salt bridge
C
a power supply
D
an aqueous solution
Subjective
1.
a)
Indicate in the blank spaces on the following chart whether or not a reaction will occur when the
metals are added to the aqueous ions.
Pd
Rh
Pt
Pd2+
Rh2+
no reaction
Pt2+
reaction
b)
2.
no reaction
reaction
List the oxidizing agents in order of strongest to weakest
Consider the following reaction for the formation of rust:
Fe(s) + ½ O2(g) + H2O(l) → Fe(OH)2
Describe and explain two methods, using different chemical principles, to prevent the formation of rust.
a)
b)
3.
Consider the following redox reaction:
H2Se + SO42- + 2H+ → Se + H2SO3 + H2O
Calculate the Eo for the reaction.
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4.
Balance the following redox reaction in basic solution:
Au
5.
+
Cl-
+
O2
→
AuCl4- +
OH-
Draw and label a simple electrolytic cell capable of electroplating and inert electrode with silver.
6.
a)
During the production of magnesium metal from seawater, magnesium ions are first precipitated
from seawater as magnesium hydroxide. The magnesium hydroxide is neutralized by hydrochloric
acid, producing magnesium chloride. Write the neutralization reaction.
b)
The salt produced, magnesium chloride, is dried melted and undergoes electrolysis. Write the
reaction at each electrode.
Anode
Cathode
c)
It is not possible to remove Mg from a 1.0 M solution. Explain why?
d)
Write the anode reaction if Cu electrodes were used instead of C.
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7.
Consider the following diagram in the electro refining of lead:
Power Source
Pure Pb
a)
On the diagram above, label the anode and cathode.
b)
Write the formula for a suitable electrolyte.
c)
Write the equation for the reduction half-reaction.
d)
Write the anode reaction
Impure Pb