Chapter 17 - Electrochemistry

Question 1 of 38

1

What is the oxidation number of bromine in the BrO3- ion?

Select one of the following:

A) -1
B) +1
C) +3
D) +5
E) +7

Explanation

Question 2 of 38

1

What is the oxidation number of sulfur in the HSO4- ion?

Select one of the following:

A) -2
B) +1
C) +2
D) +4
E) +6

Explanation

Question 3 of 38

1

Which element is oxidized in the reaction below?

Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) + H2 (g)

Select one of the following:

A) Fe
B) C
C) O
D) H
E) I

Explanation

Question 4 of 38

1

Which element is reduced in the reaction below?

Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) + H2 (g)

Select one of the following:

A) Fe
B) C
C) O
D) H
E) I

Explanation

Question 5 of 38

1

Which of the following reactions is a redox reaction?

(a) K2CrO4 + BaCl2 → BaCrO4 + 2KCl
(b) Pb22+ + 2Br- → PbBr
(c) Cu + S → CuS

Select one of the following:

A) (a) only
B) (b) only
C) (c) only
D) (a) and (c)
E) (b) and (c)

Explanation

Question 6 of 38

1

Which one of the following reactions is a redox reaction?

Select one of the following:

A) NaOH + HCl → NaCl + H2O
B) Pb2+ + 2Cl- → PbCl2
C) AgNO3 + HCl → HNO3 + AgCl
D) None of the above is a redox reaction.

Explanation

Question 7 of 38

1

Which substance is the reducing agent in the following reaction?
Fe2S3 + 12HNO3 → 2Fe(NO3)3 + 3S + 6NO2 + 6H2O

Select one of the following:

A) HNO3
B) S
C) NO2
D) Fe2S3
E) H2O

Explanation

Question 8 of 38

1

What is the coefficient of the permanganate ion when the following equation is balanced?
MnO4- + Br- → Mn2+ + Br2 (acidic solution)

Select one of the following:

A) 1
B) 2
C) 3
D) 5
E) 4

Explanation

Question 9 of 38

1

What is the coefficient of Fe3+ when the following equation is balanced?
CN- + Fe3+ → CNO- + Fe2+ (basic solution)

Select one of the following:

A) 1
B) 2
C) 3
D) 4
E) 5

Explanation

Question 10 of 38

1

The purpose of the salt bridge in an electrochemical cell is to __________.

Select one of the following:

A) maintain electrical neutrality in the half-cells via migration of ions.
B) provide a source of ions to react at the anode and cathode.
C) provide oxygen to facilitate oxidation at the anode.
D) provide a means for electrons to travel from the anode to the cathode.
E) provide a means for electrons to travel from the cathode to the anode.

Explanation

Question 11 of 38

1

Which transformation could take place at the anode of an electrochemical cell?

Select one of the following:

A) NO → NO3-
B) CO2 → Cr2O42-
C) VO2+ → VO2+
D) H2AsO4 → H3AsO3
E) O2 → H2O2

Explanation

Question 12 of 38

1

Which transformation could take place at the cathode of an electrochemical cell?

Select one of the following:

A) MnO2 → MnO4-
B) Br2 → BrO3-
C) NO → HNO2
D) HSO4- → H2SO3
E) Mn2+ → MnO4-

Explanation

Question 13 of 38

1

Which of the halogens in Table 20.1 is the strongest oxidizing agent?

Select one of the following:

A) Cl2
B) Br2
C) F2
D) I2
E) All of the halogens have equal strength as oxidizing agents.

Explanation

Question 14 of 38

1

Which one of the following types of elements is most likely to be a good oxidizing agent?

Select one of the following:

A) alkali metals
B) lanthanides
C) alkaline earth elements
D) transition elements
E) halogens

Explanation

Question 15 of 38

1

Which one of the following is the best oxidizing agent?

Select one of the following:

A) H2
B) Na
C) O2
D) Li
E) Ca

Explanation

Question 16 of 38

1

Which of the following reactions will occur spontaneously as written?

Select one of the following:

A) Sn4+ (aq) + Fe3+ (aq) → Sn2+ (aq) + Fe2+ (aq)
B) 3Fe (s) + 2Cr3+ (aq) → 2Cr (s) + 3Fe2+ (aq)
C) Sn4+ (aq) + Fe2+ (aq) → Sn2+ (aq) + Fe (s) ← I chose this one
D) 3Sn4+ (aq) + 2Cr (s) → 2Cr3+ (aq) + 3Sn2+ (aq)
E) 3Fe2+ (aq) → Fe (s) + 2Fe3+ (aq)

Explanation

Question 17 of 38

1

Consider an electrochemical cell based on the reaction:

2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g)

Which of the following actions would change the measured cell potential?

Select one of the following:

A) increasing the pH in the cathode compartment
B) lowering the pH in the cathode compartment
C) increasing the [Sn2+] in the anode compartment
D) increasing the pressure of hydrogen gas in the cathode compartment
E) Any of the above will change the measure cell potential.

Explanation

Question 18 of 38

1

Consider an electrochemical cell based on the reaction:

2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g)

Which of the following actions would not change the measured cell potential?

Select one of the following:

A) lowering the pH in the cathode compartment
B) addition of more tin metal to the anode compartment
C) increasing the tin (II) ion concentration in the anode compartment
D) increasing the pressure of hydrogen gas in the cathode compartment
E) Any of the above will change the measured cell potential.

Explanation

Question 19 of 38

1

Cathodic protection of a metal pipe against corrosion usually entails

Select one of the following:

A) attaching an active metal to make the pipe the anode in an electrochemical cell.
B) coating the pipe with another metal whose standard reduction potential is less negative than that of the pipe.
C) attaching an active metal to make the pipe the cathode in an electrochemical cell.
D) attaching a dry cell to reduce any metal ions which might be formed.
E) coating the pipe with a fluoropolymer to act as a source of fluoride ion (since the latter is so hard to oxidize).

Explanation

Question 20 of 38

1

One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell __________.

Select one of the following:

A) an electric current is produced by a chemical reaction
B) electrons flow toward the anode
C) a nonspontaneous reaction is forced to occur
D) O2 gas is produced at the cathode
E) oxidation occurs at the cathode

Explanation

Question 21 of 38

1

__________ is reduced in the following reaction:

Cr2O72- + 6S2O32- + 14H+ → 2Cr3+ + 3S4O62- + 7H2O

Select one of the following:

A) Cr6+
B) S2+
C) H+
D) O2-
E) S4O62-

Explanation

Question 22 of 38

1

Which substance is serving as the oxidizing agent in the following reaction?

14H+ + Cr2O72- + 3Ni → 3Ni2+ + 2Cr3+ + 7H2O

Select one of the following:

A) Ni
B) H+
C) Cr2O72-
D) H2O
E) Ni2+

Explanation

Question 23 of 38

1

__________ electrons appear in the following half-reaction when it is balanced.

S4O62- → S2O32-

Select one of the following:

A) 6
B) 2
C) 4
D) 1
E) 3

Explanation

Question 24 of 38

1

The balanced half-reaction in which dichromate ion is reduced to chromium metal is a __________ process.

Select one of the following:

A) two-electron
B) six-electron
C) three-electron
D) four-electron
E) twelve-electron

Explanation

Question 25 of 38

1

The electrode at which oxidation occurs is called the __________.

Select one of the following:

A) oxidizing agent
B) cathode
C) reducing agent
D) anode
E) voltaic cell

Explanation

Question 26 of 38

1

In a voltaic cell, electrons flow from the to the .

Select one of the following:

A) salt bride, anode
B) anode, salt bridge
C) cathode, anode
D) salt bridge, cathode
E) anode, cathode

Explanation

Question 27 of 38

1

The standard cell potential (E°cell) for the voltaic cell based on the reaction below is __________ V.
Sn2+ (aq) + 2Fe3+ (aq) → 2Fe2+ (aq) + Sn4+ (aq)

Select one of the following:

A) +0.46
B) +0.617
C) +1.39
D) -0.46
E) +1.21

Explanation

Question 28 of 38

1

The standard cell potential (E°cell) for the voltaic cell based on the reaction below is __________ V.

Cr (s) + 3Fe3+ (aq) → 3Fe2+ (aq) + Cr3+ (aq)

Select one of the following:

A) -1.45
B) +2.99
C) +1.51
D) +3.05
E) +1.57

Explanation

Question 29 of 38

1

The standard cell potential (E°cell) of the reaction below is +0.126 V. The value of ΔG° for the reaction is __________ kJ/mol.

Pb (s) + 2H+ (aq) → Pb2+ (aq) + H2 (g)

Select one of the following:

A) -24.3
B) +24.3
C) -12.6
D) +12.6
E) -50.8

Explanation

Question 30 of 38

1

The standard cell potential (E°cell) of the reaction below is -0.34 V. The value of ΔG° for the reaction is __________ kJ/mol.

Cu (s) + 2H+ (aq) → Cu2+ (aq) + H2 (g)

Select one of the following:

A) -0.34
B) +66
C) -130
D) +130
E) none of the above

Explanation

Question 31 of 38

1

The standard cell potential (E°cell) of the reaction below is +1.34 V. The value of ΔG° for the reaction is __________ kJ/mol.

3Cu (s) + 2MnO4- (aq) + 8H+ (aq) → 3Cu2+ (aq) + 2MnO2 (s) + 4H2O (l)

Select one of the following:

A) -24.3
B) +259
C) -259
D) +776
E) none of the above

Explanation

Question 32 of 38

1

Galvanized iron is iron coated with __________.

Select one of the following:

A) magnesium.
B) zinc.
C) chromium.
D) phosphate.
E) iron oxide.

Explanation

Question 33 of 38

1

The standard cell potential (E°) of a voltaic cell constructed using the cell reaction below is 0.76 V:

Zn (s) + 2H+ (aq) → Zn2+ (aq) + H2 (g)

With PH2 = 1.0 atm and [Zn2+] = 1.0 M, the cell potential is 0.66 V. The concentration of H+ in the cathode compartment is __________ M.

Select one of the following:

A) 2.0 × 10-2
B) 4.2 × 10-4
C) 1.4 × 10-1
D) 4.9 × 101
E) 1.0 × 10-12

Explanation

Question 34 of 38

1

A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is

AgCl (s) + e- → Ag (s) + Cl- (aq) E° = +0.222 V

The concentrations of chloride ion in the two compartments are 0.0222 M and 2.22 M, respectively. The cell emf is __________ V.

Select one of the following:

A) 0.212
B) 0.118
C) 0.00222
D) 22.2
E) 0.232

Explanation

Question 35 of 38

1

The standard cell potential (E°cell) for the reaction below is +0.63 V. The cell potential for this reaction is __________ V when [Zn2+] = 3.5 M and [Pb2+] = 2.0 × 10-4 M.

Pb2+ (aq) + Zn (s) → Zn2+ (aq) + Pb (s)

Select one of the following:

A) 0.50
B) 0.84
C) 0.39
D) 0.76
E) 0.63

Explanation

Question 36 of 38

1

The standard emf for the cell using the overall cell reaction below is +2.20 V:

2Al (s) + 3I2 (s) → 2Al3+ (aq) + 6I- (aq)

The emf generated by the cell when [Al3+] = 4.5 × 10-3 M and [I-] = 0.15 M is ________ V.

Select one of the following:

A) 2.20
B) 2.32
C) 2.10
D) 2.39
E) 2.23

Explanation

Question 37 of 38

1

The most difficult species to reduce and the poorest oxidizing agent is __________.

Select one of the following:

A) Fr+
B) F-
C) Li+
D) He

Explanation

Question 38 of 38

1

In a half reaction the amount of a substance that is reduced or oxidized is directly proportional to the number of electrons generated in the cell.

Select one of the following:

True
False

	Created by Dawn G almost 8 years ago

Originally chapter 20

Chapter 17 - Electrochemistry

Question 1 of 38

What is the oxidation number of bromine in the BrO3- ion?

Select one of the following:

Explanation

Question 2 of 38

What is the oxidation number of sulfur in the HSO4- ion?

Select one of the following:

Explanation

Question 3 of 38

Which element is oxidized in the reaction below? Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) + H2 (g)

Select one of the following:

Explanation

Question 4 of 38

Which element is reduced in the reaction below? Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) + H2 (g)

Select one of the following:

Explanation

Question 5 of 38

Which of the following reactions is a redox reaction? (a) K2CrO4 + BaCl2 → BaCrO4 + 2KCl (b) Pb22+ + 2Br- → PbBr (c) Cu + S → CuS

Select one of the following:

Explanation

Question 6 of 38

Which one of the following reactions is a redox reaction?

Select one of the following:

Explanation

Question 7 of 38

Which substance is the reducing agent in the following reaction? Fe2S3 + 12HNO3 → 2Fe(NO3)3 + 3S + 6NO2 + 6H2O

Select one of the following:

Explanation

Question 8 of 38

What is the coefficient of the permanganate ion when the following equation is balanced? MnO4- + Br- → Mn2+ + Br2 (acidic solution)

Select one of the following:

Explanation

Question 9 of 38

What is the coefficient of Fe3+ when the following equation is balanced? CN- + Fe3+ → CNO- + Fe2+ (basic solution)

Select one of the following:

Explanation

Question 10 of 38

The purpose of the salt bridge in an electrochemical cell is to __________.

Select one of the following:

Explanation

Question 11 of 38

Which transformation could take place at the anode of an electrochemical cell?

Select one of the following:

Explanation

Question 12 of 38

Which transformation could take place at the cathode of an electrochemical cell?

Select one of the following:

Explanation

Question 13 of 38

Which of the halogens in Table 20.1 is the strongest oxidizing agent?

Select one of the following:

Explanation

Question 14 of 38

Which one of the following types of elements is most likely to be a good oxidizing agent?

Select one of the following:

Explanation

Question 15 of 38

Which one of the following is the best oxidizing agent?

Select one of the following:

Explanation

Question 16 of 38

Which of the following reactions will occur spontaneously as written?

Select one of the following:

Explanation

Question 17 of 38

Consider an electrochemical cell based on the reaction: 2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g) Which of the following actions would change the measured cell potential?

Select one of the following:

Explanation

Question 18 of 38

Consider an electrochemical cell based on the reaction: 2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g) Which of the following actions would not change the measured cell potential?

Select one of the following:

Explanation

Question 19 of 38

Cathodic protection of a metal pipe against corrosion usually entails

Select one of the following:

Explanation

Question 20 of 38

One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell __________.

Which element is oxidized in the reaction below?

Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) + H2 (g)

Which element is reduced in the reaction below?

Fe(CO)5 (l) + 2HI (g) → Fe(CO)4I2 (s) + CO (g) + H2 (g)

Which of the following reactions is a redox reaction?

(a) K2CrO4 + BaCl2 → BaCrO4 + 2KCl
(b) Pb22+ + 2Br- → PbBr
(c) Cu + S → CuS

Which substance is the reducing agent in the following reaction?
Fe2S3 + 12HNO3 → 2Fe(NO3)3 + 3S + 6NO2 + 6H2O

What is the coefficient of the permanganate ion when the following equation is balanced?
MnO4- + Br- → Mn2+ + Br2 (acidic solution)

What is the coefficient of Fe3+ when the following equation is balanced?
CN- + Fe3+ → CNO- + Fe2+ (basic solution)

Consider an electrochemical cell based on the reaction:

2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g)

Which of the following actions would change the measured cell potential?

Consider an electrochemical cell based on the reaction:

2H+ (aq) + Sn (s) → Sn2+ (aq) + H2 (g)

Which of the following actions would not change the measured cell potential?

__________ is reduced in the following reaction:

Cr2O72- + 6S2O32- + 14H+ → 2Cr3+ + 3S4O62- + 7H2O

Which substance is serving as the oxidizing agent in the following reaction?

14H+ + Cr2O72- + 3Ni → 3Ni2+ + 2Cr3+ + 7H2O

__________ electrons appear in the following half-reaction when it is balanced.

S4O62- → S2O32-

In a voltaic cell, electrons flow from the to the .

The standard cell potential (E°cell) for the voltaic cell based on the reaction below is __________ V.
Sn2+ (aq) + 2Fe3+ (aq) → 2Fe2+ (aq) + Sn4+ (aq)

The standard cell potential (E°cell) for the voltaic cell based on the reaction below is __________ V.

Cr (s) + 3Fe3+ (aq) → 3Fe2+ (aq) + Cr3+ (aq)

The standard cell potential (E°cell) of the reaction below is +0.126 V. The value of ΔG° for the reaction is __________ kJ/mol.

Pb (s) + 2H+ (aq) → Pb2+ (aq) + H2 (g)

The standard cell potential (E°cell) of the reaction below is -0.34 V. The value of ΔG° for the reaction is __________ kJ/mol.

Cu (s) + 2H+ (aq) → Cu2+ (aq) + H2 (g)

The standard cell potential (E°cell) of the reaction below is +1.34 V. The value of ΔG° for the reaction is __________ kJ/mol.

3Cu (s) + 2MnO4- (aq) + 8H+ (aq) → 3Cu2+ (aq) + 2MnO2 (s) + 4H2O (l)

The standard cell potential (E°) of a voltaic cell constructed using the cell reaction below is 0.76 V:

Zn (s) + 2H+ (aq) → Zn2+ (aq) + H2 (g)

With PH2 = 1.0 atm and [Zn2+] = 1.0 M, the cell potential is 0.66 V. The concentration of H+ in the cathode compartment is __________ M.

A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is

AgCl (s) + e- → Ag (s) + Cl- (aq) E° = +0.222 V

The concentrations of chloride ion in the two compartments are 0.0222 M and 2.22 M, respectively. The cell emf is __________ V.

The standard cell potential (E°cell) for the reaction below is +0.63 V. The cell potential for this reaction is __________ V when [Zn2+] = 3.5 M and [Pb2+] = 2.0 × 10-4 M.

Pb2+ (aq) + Zn (s) → Zn2+ (aq) + Pb (s)

The standard emf for the cell using the overall cell reaction below is +2.20 V:

2Al (s) + 3I2 (s) → 2Al3+ (aq) + 6I- (aq)

The emf generated by the cell when [Al3+] = 4.5 × 10-3 M and [I-] = 0.15 M is ________ V.