Question 1

What is the half-reaction that occurs at the cathode during electrolysis of an aqueous potassium iodide solution?
Reduction Half-Reaction
E° (V)
K+(aq)+ e- K(s) -2.93
Mg2+(aq)+ 2e- Mg(s) -2.37
2H2O(l)+ 2e- H2(g)+ 2OH-(aq) -0.83
2H+(aq)+ 2e- H2(g) 0.00
I2(s)+ 2e- 2I-(aq) 0.54
O2(g)+ 4H+(aq)+ 4e- 2H2O(l) 1.23

Accepted Answer

A) H2O(l)→ 1/2 O2(g)+ 2H+(aq)+ 2e- 
B) 2H2O(l)+ 2e- → H2(g)+ 2OH-(aq) 
C) K(s)→ K+(aq)+ e- 
D) K+(aq)+ e- → K(s) 
E) I2(aq)+ 2e- → 2I-(aq)

Question 2

What is E°cell for the cell reaction 2Cr(s)+ 3Sn4+ (aq​)→ 3Sn2+(aq)+ 2Cr3+ (aq​)?
Cr3+ (aq​)+ 3e- Cr(s); E° = -0.74V 
 
​

Accepted Answer

A) 0.89V 
B) -0.59V 
C)   
D)   
E) 0.59V

Question 3

The cell potential of an electrochemical cell with the cell reaction
Al(s)+ Cr3+(aq)→ Cr(s)+ Al3+(aq)
Is 1.63 V.What is the maximum electrical work obtainable from this cell when 0.50 g of Al is consumed?

Accepted Answer

A)   J 
B)   J 
C)   J 
D)   J 
E)   J

Question 4

If an electrolysis plant operates its electrolytic cells at a total current of 1.4 × 106 A,how long will it take to produce one metric ton (one million grams)of Mg(s)from seawater containing Mg2+? (1 faraday = 96,485 coulombs)

Accepted Answer

A) 47 min 
B) 0.39 year 
C) 1.6 h 
D) 1.6 days 
E) 0.8 h

Question 5

Molten magnesium chloride is electrolyzed using inert electrodes and reactions represented by the following two half-reactions:
2Cl-(l)→ Cl2(g)+ 2e-
Mg2+(l)+ 2e- → Mg(s)
Concerning this electrolysis,which of the following statements is true?

Accepted Answer

A) The anions in the electrolyte undergo reduction. 
B) Mg2+ ions are reduced at the anode. 
C) Oxidation occurs at the cathode. 
D) Electrons pass through the metallic part of the circuit from Mg2+ ions to the Cl- ion. 
E) Cl- ions are reducing agents.

Question 6

Consider the following cell reaction:
2Cr(s)+ 6H+(aq)→ 2Cr3+(aq)+ 3H2(g); E°cell = 0.74V
Under standard-state conditions,what is E° for the following half-reaction?
Cr3+(aq)+ 3e− → Cr(s)

Accepted Answer

A) -0.74 V 
B)   
C) -0.37 V 
D) 0.37 V 
E) 0.74 V

Question 7

Consider the following reduction potentials:
Cd2+(aq)+ 2e- Cd(s); E° = -0.40 V
Pb2+(aq)+ 2e- Pb(s); E° = -0.13 V
Cu2+(aq)+ 2e- Cu(s); E° = 0.34 V
Br2(l)+ 2e- 2Br-(aq); E° = 1.07 V
Under standard-state conditions,which of the following reactions is spontaneous?

Accepted Answer

A) Cd2+(aq)+ Pb(s)→ Cd(s)+ Pb2+(aq) 
B) Pb2+(aq)+ Cu(s)→ Pb(s)+ Cu2+(aq) 
C) 2Br-(aq)+ Pb2+(aq)→ Br2(l)+ Pb(s) 
D) 2Br-(aq)+ Cu2+(aq)→ Br2(l)+ Cu(s) 
E) Cu2+(aq)+ Cd(s)→ Cu(s)+ Cd2+(aq)

Question 8

Which reaction would be most likely to occur at the anode of a voltaic cell?

Accepted Answer

A) PbSO4(s)+ 2e- → Pb(s)+ SO42-(aq) 
B) 2H2O(l)+ 2e- → H2(g)+ 2OH-(aq) 
C) 2H2O(l)→ O2(g)+ 4H+(aq)+ 4e- 
D) PbSO4(s)→ Pb2+(aq)+ SO42-(aq) 
E) 2H2O(l)→ 2H2(g)+ O2(g)

Question 9

Consider the following standard reduction potentials:
2H+(aq)+ 2e- H2(g); E° = 0.00 V
Sn2+(aq)+ 2e- Sn(s); E° = -0.15 V
Cd2+(aq)+ 2e- Cd(s); E° = -0.40 V
Which pair of substances will react spontaneously under standard-state conditions?

Accepted Answer

A) Cd with H+ 
B) Cd with Sn 
C) Sn2+ with Cd2+ 
D) Sn with Cd2+ 
E) Sn2+ with H+

Question 10

Which of the following cell reactions would require the use of an inert electrode?

Accepted Answer

A) Cu(s)+ 2Ag+(aq)→ 2Ag(s)+ Cu2+(aq) 
B) 3Fe(s)+ 2Au3+(aq)→ 3Fe2+ + 2Au(s) 
C) Zn(s)+ 2Ag+(aq)→ Zn2+(aq)+ 2Ag(s) 
D) Ni(s)+ 2MnO2(s)+ 2NH4+(aq)→ Ni2+(aq)+ Mn2O3(s)+ 2NH3(aq)+ H2O(l) 
E) 3Zn2+(aq)+ 2Al(s)→ 3Zn(s)+ 2Al3+(aq)

Question 11

Which of the following statements is true about a voltaic cell for which E°cell = 1.00 V?

Accepted Answer

A) The cathode is at a higher energy than the anode. 
B) It has ΔG° > 0. 
C) The reaction is spontaneous. 
D) The system is at equilibrium. 
E) It has K = 1.

Question 12

Consider the following standard electrode potentials:
Ag+(aq)+ e- Ag(s); E° = 0.80 V
Mn2+(aq)+ 2e- Mn(s); E° = -1.18 V
Which of the following statements is false concerning the electrochemical cell given below?
Mn(s)| Mn2+(aq)|| Ag+(aq)| Ag(s)

Accepted Answer

A) The anode half-cell reaction is Mn(s)→ Mn2+(aq)+ 2e-. 
B) The reducing agent is Ag(s). 
C) Under standard-state conditions,the cell potential is 1.98 V. 
D) The cell potential decreases with time. 
E) The oxidizing agent is Ag+(aq).

Question 13

Copper is electroplated from CuSO4 solution.A constant current of 4.06 A is applied by an external power supply.How long will it take to deposit 1.00 ×102 g of Cu? The atomic weight of copper is 63.546.

Accepted Answer

A) 20.8 h 
B) 12.18 s 
C) 1.60 days 
D) 10.4 min 
E) 2.97 h

Question 14

Consider the following cell reaction:
2Hg2+(aq)+ H2(g)→ 2H+(aq)+ Hg22+(aq); E°cell = 0.92 V
Under standard-state conditions,what is E° for the following half-reaction?
Hg2+(aq)+ 2e- → Hg22+(aq)

Accepted Answer

A) 0.92 V 
B) -0.46 V 
C) 0.46 V 
D) -0.92 V 
E) 1.10 V

Question 15

Which of the following statements is true concerning the electrochemical cell depicted below?
Zn | Zn2+(aq)|| Cu2+(aq)| Cu
Zn2+(aq)+ 2e− Zn(s); E° = -2.87 V
Cu2+(aq)+ 2e− Cu(s); E° = -2.38 V

Accepted Answer

A) The cell is at equilibrium. 
B) The cell reaction is spontaneous with a standard cell potential of 0.49 V. 
C) The cell reaction is spontaneous with a standard cell potential of 5.25 V. 
D) The cell reaction is nonspontaneous with a standard cell potential of -5.25 V. 
E) The cell reaction is nonspontaneous with a standard cell potential of -0.49 V.

Question 16

Which of the following statements is true concerning the voltaic cell shown below?

Accepted Answer

A) The Zn anode mass decreases as the cell discharges. 
B) The Zn cathode mass increases as the cell discharges. 
C) The Zn cathode mass decreases as the cell discharges. 
D) The Zn anode mass increases as the cell discharges. 
E) The mass of the Zn electrode neither increases nor decreases as the cell discharges.

Question 17

An amalgam is an alloy of _____ with any other metal.

Accepted Answer

A) ​mercury 
B) ​copper (II) 
C) ​iron (II) 
D) ​potassium 
E) ​zinc

Question 18

How many faradays are involved in the conversion of a mole of Mn2O3 to MnO2 ?

Accepted Answer

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

Question 19

What half-reaction occurs at the cathode during the electrolysis of molten potassium bromide?

Accepted Answer

A) K(s)→ K+(l)+ e- 
B) Br2(l)+ 2e- → 2Br-(l) 
C) 2Br-(l)→ Br2(l)+ 2e- 
D) K+(l)+ e- → K(s) 
E) 2H2O(l)+ 2e- → H2(g)+ 2OH-(l)

Question 20

A voltaic cell is made by placing a zinc electrode in a compartment in which the Zn2+ concentration is 2.0 × 10-5 M and by placing a Pt electrode in the other compartment,in which the H+ concentration is 3.4 M and PH2 = 1.00 atm.The Zn2+/Zn half-cell reduction potential is -0.76 V,and the H+/H2 half-cell reduction potential is 0.00 V.What is the equilibrium constant at 25°C for the spontaneous cell reaction?

Accepted Answer

A) 4 × 104 
B) 5 × 1020 
C) 5 × 1022 
D) 7 × 10 12 
E) 5 × 10 25

Exam 19: Electrochemistry

What is E°_cell for the cell reaction 2Cr(s) + 3Sn⁴⁺ (aq) → 3Sn²⁺(aq) + 2Cr³⁺ (aq) ? Cr³⁺(aq) + 3e^- Cr(s) ; E° = -0.74V

The cell potential of an electrochemical cell with the cell reaction Al(s) + Cr³⁺(aq) → Cr(s) + Al³⁺(aq) Is 1.63 V.What is the maximum electrical work obtainable from this cell when 0.50 g of Al is consumed?

If an electrolysis plant operates its electrolytic cells at a total current of 1.4 × 10⁶ A,how long will it take to produce one metric ton (one million grams) of Mg(s) from seawater containing Mg²⁺? (1 faraday = 96,485 coulombs)

Molten magnesium chloride is electrolyzed using inert electrodes and reactions represented by the following two half-reactions: 2Cl^-(l) → Cl₂(g) + 2e^- Mg²⁺(l) + 2e^- → Mg(s) Concerning this electrolysis,which of the following statements is true?

Consider the following cell reaction: 2Cr(s) + 6H⁺(aq) → 2Cr³⁺(aq) + 3H₂(g) ; E°_cell = 0.74V Under standard-state conditions,what is E° for the following half-reaction? Cr³⁺(aq) + 3e− → Cr(s)

Consider the following reduction potentials: Cd²⁺(aq) + 2e^- Cd(s) ; E° = -0.40 V Pb²⁺(aq) + 2e^- Pb(s) ; E° = -0.13 V Cu²⁺(aq) + 2e^- Cu(s) ; E° = 0.34 V Br₂(l) + 2e^- 2Br^-(aq) ; E° = 1.07 V Under standard-state conditions,which of the following reactions is spontaneous?

Which reaction would be most likely to occur at the anode of a voltaic cell?

Consider the following standard reduction potentials: 2H⁺(aq) + 2e^- H₂(g) ; E° = 0.00 V Sn²⁺(aq) + 2e^- Sn(s) ; E° = -0.15 V Cd²⁺(aq) + 2e^- Cd(s) ; E° = -0.40 V Which pair of substances will react spontaneously under standard-state conditions?

Which of the following cell reactions would require the use of an inert electrode?

Which of the following statements is true about a voltaic cell for which E°_cell = 1.00 V?

Consider the following standard electrode potentials: Ag⁺(aq) + e^- Ag(s) ; E° = 0.80 V Mn²⁺(aq) + 2e^- Mn(s) ; E° = -1.18 V Which of the following statements is false concerning the electrochemical cell given below? Mn(s) | Mn²⁺(aq) || Ag⁺(aq) | Ag(s)

Copper is electroplated from CuSO₄ solution.A constant current of 4.06 A is applied by an external power supply.How long will it take to deposit 1.00 ×10² g of Cu? The atomic weight of copper is 63.546.

Consider the following cell reaction: 2Hg²⁺(aq) + H₂(g) → 2H⁺(aq) + Hg₂²⁺(aq) ; E°_cell = 0.92 V Under standard-state conditions,what is E° for the following half-reaction? Hg²⁺(aq) + 2e^- → Hg₂²⁺(aq)

Which of the following statements is true concerning the electrochemical cell depicted below? Zn | Zn²⁺(aq) || Cu²⁺(aq) | Cu Zn²⁺(aq) + 2e− Zn(s) ; E° = -2.87 V Cu²⁺(aq) + 2e− Cu(s) ; E° = -2.38 V

Which of the following statements is true concerning the voltaic cell shown below?

An amalgam is an alloy of _____ with any other metal.

How many faradays are involved in the conversion of a mole of Mn₂O₃ to MnO₂?

What half-reaction occurs at the cathode during the electrolysis of molten potassium bromide?

Exam 19: Electrochemistry

What is E°cell for the cell reaction 2Cr(s) + 3Sn4+ (aq​) → 3Sn2+(aq) + 2Cr3+ (aq​) ? Cr3+ (aq​) + 3e- Cr(s) ; E° = -0.74V ​

The cell potential of an electrochemical cell with the cell reaction Al(s) + Cr3+(aq) → Cr(s) + Al3+(aq) Is 1.63 V.What is the maximum electrical work obtainable from this cell when 0.50 g of Al is consumed?

If an electrolysis plant operates its electrolytic cells at a total current of 1.4 × 106 A,how long will it take to produce one metric ton (one million grams) of Mg(s) from seawater containing Mg2+? (1 faraday = 96,485 coulombs)

Molten magnesium chloride is electrolyzed using inert electrodes and reactions represented by the following two half-reactions: 2Cl-(l) → Cl2(g) + 2e- Mg2+(l) + 2e- → Mg(s) Concerning this electrolysis,which of the following statements is true?

Consider the following cell reaction: 2Cr(s) + 6H+(aq) → 2Cr3+(aq) + 3H2(g) ; E°cell = 0.74V Under standard-state conditions,what is E° for the following half-reaction? Cr3+(aq) + 3e− → Cr(s)

Consider the following reduction potentials: Cd2+(aq) + 2e- Cd(s) ; E° = -0.40 V Pb2+(aq) + 2e- Pb(s) ; E° = -0.13 V Cu2+(aq) + 2e- Cu(s) ; E° = 0.34 V Br2(l) + 2e- 2Br-(aq) ; E° = 1.07 V Under standard-state conditions,which of the following reactions is spontaneous?

Which reaction would be most likely to occur at the anode of a voltaic cell?

Consider the following standard reduction potentials: 2H+(aq) + 2e- H2(g) ; E° = 0.00 V Sn2+(aq) + 2e- Sn(s) ; E° = -0.15 V Cd2+(aq) + 2e- Cd(s) ; E° = -0.40 V Which pair of substances will react spontaneously under standard-state conditions?

Which of the following cell reactions would require the use of an inert electrode?

Which of the following statements is true about a voltaic cell for which E°cell = 1.00 V?

Consider the following standard electrode potentials: Ag+(aq) + e- Ag(s) ; E° = 0.80 V Mn2+(aq) + 2e- Mn(s) ; E° = -1.18 V Which of the following statements is false concerning the electrochemical cell given below? Mn(s) | Mn2+(aq) || Ag+(aq) | Ag(s)

Copper is electroplated from CuSO4 solution.A constant current of 4.06 A is applied by an external power supply.How long will it take to deposit 1.00 ×102 g of Cu? The atomic weight of copper is 63.546.

Consider the following cell reaction: 2Hg2+(aq) + H2(g) → 2H+(aq) + Hg22+(aq) ; E°cell = 0.92 V Under standard-state conditions,what is E° for the following half-reaction? Hg2+(aq) + 2e- → Hg22+(aq)

Which of the following statements is true concerning the electrochemical cell depicted below? Zn | Zn2+(aq) || Cu2+(aq) | Cu Zn2+(aq) + 2e− Zn(s) ; E° = -2.87 V Cu2+(aq) + 2e− Cu(s) ; E° = -2.38 V

Which of the following statements is true concerning the voltaic cell shown below?

An amalgam is an alloy of _____ with any other metal.

How many faradays are involved in the conversion of a mole of Mn2O3 to MnO2 ?

What half-reaction occurs at the cathode during the electrolysis of molten potassium bromide?

What is E°_cell for the cell reaction 2Cr(s) + 3Sn⁴⁺ (aq) → 3Sn²⁺(aq) + 2Cr³⁺ (aq) ? Cr³⁺(aq) + 3e^- Cr(s) ; E° = -0.74V

The cell potential of an electrochemical cell with the cell reaction Al(s) + Cr³⁺(aq) → Cr(s) + Al³⁺(aq) Is 1.63 V.What is the maximum electrical work obtainable from this cell when 0.50 g of Al is consumed?

If an electrolysis plant operates its electrolytic cells at a total current of 1.4 × 10⁶ A,how long will it take to produce one metric ton (one million grams) of Mg(s) from seawater containing Mg²⁺? (1 faraday = 96,485 coulombs)

Molten magnesium chloride is electrolyzed using inert electrodes and reactions represented by the following two half-reactions: 2Cl^-(l) → Cl₂(g) + 2e^- Mg²⁺(l) + 2e^- → Mg(s) Concerning this electrolysis,which of the following statements is true?

Consider the following cell reaction: 2Cr(s) + 6H⁺(aq) → 2Cr³⁺(aq) + 3H₂(g) ; E°_cell = 0.74V Under standard-state conditions,what is E° for the following half-reaction? Cr³⁺(aq) + 3e− → Cr(s)

Consider the following reduction potentials: Cd²⁺(aq) + 2e^- Cd(s) ; E° = -0.40 V Pb²⁺(aq) + 2e^- Pb(s) ; E° = -0.13 V Cu²⁺(aq) + 2e^- Cu(s) ; E° = 0.34 V Br₂(l) + 2e^- 2Br^-(aq) ; E° = 1.07 V Under standard-state conditions,which of the following reactions is spontaneous?

Consider the following standard reduction potentials: 2H⁺(aq) + 2e^- H₂(g) ; E° = 0.00 V Sn²⁺(aq) + 2e^- Sn(s) ; E° = -0.15 V Cd²⁺(aq) + 2e^- Cd(s) ; E° = -0.40 V Which pair of substances will react spontaneously under standard-state conditions?

Which of the following statements is true about a voltaic cell for which E°_cell = 1.00 V?

Consider the following standard electrode potentials: Ag⁺(aq) + e^- Ag(s) ; E° = 0.80 V Mn²⁺(aq) + 2e^- Mn(s) ; E° = -1.18 V Which of the following statements is false concerning the electrochemical cell given below? Mn(s) | Mn²⁺(aq) || Ag⁺(aq) | Ag(s)

Copper is electroplated from CuSO₄ solution.A constant current of 4.06 A is applied by an external power supply.How long will it take to deposit 1.00 ×10² g of Cu? The atomic weight of copper is 63.546.

Consider the following cell reaction: 2Hg²⁺(aq) + H₂(g) → 2H⁺(aq) + Hg₂²⁺(aq) ; E°_cell = 0.92 V Under standard-state conditions,what is E° for the following half-reaction? Hg²⁺(aq) + 2e^- → Hg₂²⁺(aq)

Which of the following statements is true concerning the electrochemical cell depicted below? Zn | Zn²⁺(aq) || Cu²⁺(aq) | Cu Zn²⁺(aq) + 2e− Zn(s) ; E° = -2.87 V Cu²⁺(aq) + 2e− Cu(s) ; E° = -2.38 V

How many faradays are involved in the conversion of a mole of Mn₂O₃ to MnO₂?