Question 1

Which of the following statements about voltaic and electrolytic cells is correct?

Accepted Answer

A)  The anode will definitely gain weight in a voltaic cell.
B)  Oxidation occurs at the cathode of both cells.
C)  The free energy change, Δ G, is negative for the voltaic cell.
D)  The electrons in the external wire flow from cathode to anode in an electrolytic cell.
E)  None of these choices are correct.

Question 2

Calculate ΔG° for the reaction of iron(II)  ions with one mole of permanganate ions. MnO4−(aq)  + 8H+(aq)  + 5e− ⇄ Mn2+(aq)  + 4H2O(l)  E° = 1.51 V
Fe3+(aq)  + e− ⇄ Fe2+(aq)  E°= 0.77 V

Accepted Answer

A)  −71.4 kJ
B)  −286 kJ
C)  −357 kJ
D)  −428 kJ
E)  None of these choices are correct.

Question 3

A voltaic cell can be prepared from copper and tin. What is the E°cell for the cell that forms from the following half-reactions? Cu2+(aq)  + 2e− ⇄ Cu(s)  E° = 0.34 V
Sn4+(aq)  + 2e− ⇄ Sn2+(aq)  E° = 0.13 V

Accepted Answer

A)  0.47 V
B)  0.21 V
C)  -0.21 V
D)  -0.47 V
E)  0.42 V

Question 4

Consider the reaction in the lead-acid cell Pb(s)  + PbO2(s)  + 2H2SO4(aq)  → 2PbSO4(aq)  + 2H2O(l) 
For which E°cell = 2.04 V at 298 K. ΔG° for this reaction is

Accepted Answer

A)  −3.94 × 10 5 kJ.
B)  −3.94 × 10 2 kJ.
C)  −1.97 × 10 5 kJ.
D)  −7.87 × 10 2 kJ.
E)  None of these choices are correct.

Question 5

Which, if any, of the following metals would be capable of acting as a sacrificial anode when used with iron pipe? E°Fe = −0.44 V; all E° values refer to the M2+/M half-cell reactions.

Accepted Answer

A)  copper, Cu, E° = 0.15 V
B)  cobalt, Co, E° = −0.28 V
C)  chromium, Cr, E° = −0.74 V
D)  tin, Sn, E° = −0.14 V
E)  None of these metals would be capable of acting as a sacrificial anode with iron.

Question 6

The value of the equilibrium constant for the reaction of nickel(II)  ions with cadmium metal is 1.17 × 105. Calculate ΔG° for the reaction at 25°C.

Accepted Answer

A)  −12.6 kJ
B)  −28.9 kJ
C)  12.6 kJ
D)  28.9 kJ
E)  None of these choices are correct.

Question 7

A concentration cell consists of two Al/Al3+electrodes. The electrolyte in compartment A is 0.050 M Al(NO3) 3 and in compartment B is 1.25 M Al(NO3) 3. What is the voltage of the cell at 25°C?

Accepted Answer

A)  0.083 V
B)  0.062 V
C)  0.041 V
D)  0.028 V
E)  None of these choices are correct.

Question 8

In the electrolysis of aqueous sodium sulfate at electrodes of platinum, predict the products of the cell reaction.

Accepted Answer

A)  Sodium and Sulfur
B)  Hydrogen and Sulfur
C)  Oxygen and Sulfur
D)  Oxygen and Sulfuric acid
E)  Hydrogen and Oxygen E

Question 9

A voltaic cell prepared using aluminum and nickel has the following cell notation. Al(s)  | Al3+(aq)  || Ni2+(aq)  | Ni(s) 
Which of the following reactions occurs at the anode?

Accepted Answer

A)  Al( s) → Al 3+( aq) + 3e −
B)  Al 3+( aq) + 3e → Al( s) 
C)  Ni( s) → Ni 2+( aq) + 2e −
D)  Ni 2+( aq) + 2e − → Ni( s) 
E)  None of these choices are correct.

Question 10

A voltaic cell is prepared using copper and silver. Its cell notation is shown below. Cu(s)  | Cu2+(aq)  || Ag+(aq)  | Ag(s) 
Which of the following processes occurs at the cathode?

Accepted Answer

A)  Cu( s) → Cu 2+( aq) + 2e −
B)  Cu 2+( aq) + 2e − → Cu( s) 
C)  Ag( s) → Ag +( aq) + e −
D)  Ag +( aq) + e − → Ag( s) 
E)  Cu( s) + 2Ag +( aq) → Cu 2+( aq) + 2Ag( s)

Question 11

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be __________. I2(s)  + HNO3(aq)  → HIO3(aq)  + NO2(g)  + H2O(l)

Accepted Answer

A)  1
B)  2
C)  4
D)  10
E)  None of these choices are correct.

Question 12

A voltaic cell is based on the following two half-reactions: Ni+2(aq)  + 2e− → Ni(s)  E° = −0.25 V
Cr+3(aq)  + 3e- → Cr(s)  E° = -0.74 V
Sketch the cell and then select the correct statement about it.

Accepted Answer

A)  Cr serves as the cathode.
B)  The direction of electron flow through the external wire is from the Ni to the Cr electrode.
C)  Anions in solution will migrate toward the Ni +2/Ni electrode.
D)  The net cell reaction is 3Ni +2( aq) + 2Cr( s) → 3Ni( s) + 2Cr +3( aq) 
E)  = 0.99 V

Question 13

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be Al(s)  + HSO4(aq)  + OH−(aq)  → Al2O3(s)  + S2−(aq)  + H2O(l)

Accepted Answer

A)  1.
B)  3.
C)  4.
D)  8.
E)  None of these choices are correct.

Question 14

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be I−(aq)  + NO3−(aq)  → NO(g)  + I2(s)  (acidic solution)

Accepted Answer

A)  2.
B)  3.
C)  6.
D)  8.
E)  None of these choices are correct.

Question 15

In the shorthand notation for cells, a double vertical line is used to separate the reduced and oxidized forms of a redox couple.

Accepted Answer

A) True 
 B)False

Question 16

The following half-reactions occur in the mercury battery used in calculators. If E°cell = 1.357 V, calculate the equilibrium constant for the cell reaction at 25°C. (Assume the stoichiometric coefficients in the cell reaction are all equal to 1.)  HgO(s)  + H2O(l)  + 2e− ⇄ Hg(l)  + 2OH−(aq) 
ZnO(s)  + H2O(l)  + 2e− ⇄ Zn(s)  + 2OH−(aq)

Accepted Answer

A)  9.4 × 10 22
B)  7.5 × 10 45
C)  6.4 × 10 63
D)  7.8 × 10 91
E)  > 9.9 × 10 99

Question 17

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°cell = 0.30 V Sn2+(aq)  + Fe(s)  ⇄ Sn(s)  + Fe2+(aq)

Accepted Answer

A)  1.2 × 10 5
B)  1.4 × 10 10
C)  8.6 × 10 −6
D)  7.1 × 10 −11
E)  2.3 × 10 23

Question 18

The redox reaction of peroxydisulfate with iodide has been used for many years as part of the iodine clock reaction which introduces students to kinetics. If E°cell = 1.587 V and E° of the cathode half-cell is 0.536 V, what is E° of the anode half-cell? S2O82−(aq)  + 2H+ + 2I−(aq)  → 2HSO4−(aq)  + I2(aq)

Accepted Answer

A)  -1.051 V
B)  -2.123 V
C)  1.051 V
D)  2.123 V
E)  None of these choices are correct. A

Question 19

Consider the following balanced redox reaction Mn2+(aq)  + S2O82−(aq)  + 2H2O(l)  → MnO2(s)  + 4H(aq)  + 2SO42−(aq) 
Which of the following statements is true?

Accepted Answer

A)  Mn 2+( aq) is the oxidizing agent and is reduced.
B)  Mn 2+( aq) is the oxidizing agent and is oxidized.
C)  Mn 2+( aq) is the reducing agent and is oxidized.
D)  Mn 2+( aq) is the reducing agent and is reduced.
E)  Manganese does not change its oxidation number in this reaction.

Question 20

Consider the reaction of iodine with manganese dioxide 3I2(s)  + 2MnO2(s)  + 8OH-(aq)  ⇄ 6I−(aq)  + 2MnO4(aq)  + 4H2O(l) 
The equilibrium constant for the overall reaction is 8.30 × 10−7. Calculate E°cell for the reaction at 25°C.

Accepted Answer

A)  −0.36 V
B)  −0.18 V
C)  −0.12 V
D)  −0.060 V
E)  None of these choices are correct. D

Exam 21: Electrochemistry: Chemical Change and Electrical Work

Which of the following statements about voltaic and electrolytic cells is correct?

Correct Answer
verified

Calculate ΔG° for the reaction of iron(II) ions with one mole of permanganate ions. MnO₄⁻(aq) + 8H⁺(aq) + 5e⁻ ⇄ Mn²⁺(aq) + 4H₂O(l) E° = 1.51 V Fe³⁺(aq) + e⁻ ⇄ Fe²⁺(aq) E°= 0.77 V

Correct Answer
verified

A voltaic cell can be prepared from copper and tin. What is the E°_cell for the cell that forms from the following half-reactions? Cu²⁺(aq) + 2e⁻⇄ Cu(s) E° = 0.34 V Sn⁴⁺(aq) + 2e⁻ ⇄ Sn²⁺(aq) E° = 0.13 V

Correct Answer
verified

Consider the reaction in the lead-acid cell Pb(s) + PbO₂(s) + 2H₂SO₄(aq) → 2PbSO₄(aq) + 2H₂O(l) For which E°_cell = 2.04 V at 298 K. ΔG° for this reaction is

Correct Answer
verified

Which, if any, of the following metals would be capable of acting as a sacrificial anode when used with iron pipe? E°_Fe = −0.44 V; all E° values refer to the M²⁺/M half-cell reactions.

Correct Answer
verified

The value of the equilibrium constant for the reaction of nickel(II) ions with cadmium metal is 1.17 × 10⁵. Calculate ΔG° for the reaction at 25°C.

Correct Answer
verified

A concentration cell consists of two Al/Al³⁺electrodes. The electrolyte in compartment A is 0.050 M Al(NO₃) ₃and in compartment B is 1.25 M Al(NO₃) ₃. What is the voltage of the cell at 25°C?

Correct Answer
verified

In the electrolysis of aqueous sodium sulfate at electrodes of platinum, predict the products of the cell reaction.

Correct Answer
verified
E

A voltaic cell prepared using aluminum and nickel has the following cell notation. Al(s) | Al³⁺(aq) || Ni²⁺(aq) | Ni(s) Which of the following reactions occurs at the anode?

Correct Answer
verified

A voltaic cell is prepared using copper and silver. Its cell notation is shown below. Cu(s) | Cu²⁺(aq) || Ag⁺(aq) | Ag(s) Which of the following processes occurs at the cathode?

Correct Answer
verified

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be __________. I₂(s) + HNO₃(aq) → HIO₃(aq) + NO₂(g) + H₂O(l)

Correct Answer
verified

A voltaic cell is based on the following two half-reactions: Ni⁺²(aq) + 2e⁻ → Ni(s) E° = −0.25 V Cr⁺³(aq) + 3e^- → Cr(s) E° = -0.74 V Sketch the cell and then select the correct statement about it.

Correct Answer
verified

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be Al(s) + HSO₄(aq) + OH⁻(aq) → Al₂O₃(s) + S²⁻(aq) + H₂O(l)

Correct Answer
verified

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be I⁻(aq) + NO₃⁻(aq) → NO(g) + I₂(s) (acidic solution)

Correct Answer
verified

In the shorthand notation for cells, a double vertical line is used to separate the reduced and oxidized forms of a redox couple.

Correct Answer
verified

Correct Answer
verified

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°_cell = 0.30 V Sn²⁺(aq) + Fe(s) ⇄ Sn(s) + Fe²⁺(aq)

Correct Answer
verified

Correct Answer
verified
A

Consider the following balanced redox reaction Mn²⁺(aq) + S₂O₈²⁻(aq) + 2H₂O(l) → MnO₂(s) + 4H(aq) + 2SO₄²⁻(aq) Which of the following statements is true?

Correct Answer
verified

Consider the reaction of iodine with manganese dioxide 3I₂(s) + 2MnO₂(s) + 8OH^-(aq) ⇄ 6I⁻(aq) + 2MnO₄(aq) + 4H₂O(l) The equilibrium constant for the overall reaction is 8.30 × 10⁻⁷. Calculate E°_cell for the reaction at 25°C.

Correct Answer
verified
D

Exam 21: Electrochemistry: Chemical Change and Electrical Work

Which of the following statements about voltaic and electrolytic cells is correct?

Correct AnswerverifiedShow Answer

Calculate ΔG° for the reaction of iron(II) ions with one mole of permanganate ions. MnO4−(aq) + 8H+(aq) + 5e− ⇄ Mn2+(aq) + 4H2O(l) E° = 1.51 V Fe3+(aq) + e− ⇄ Fe2+(aq) E°= 0.77 V

Correct AnswerverifiedShow Answer

A voltaic cell can be prepared from copper and tin. What is the E°cell for the cell that forms from the following half-reactions? Cu2+(aq) + 2e− ⇄ Cu(s) E° = 0.34 V Sn4+(aq) + 2e− ⇄ Sn2+(aq) E° = 0.13 V

Correct AnswerverifiedShow Answer

Consider the reaction in the lead-acid cell Pb(s) + PbO2(s) + 2H2SO4(aq) → 2PbSO4(aq) + 2H2O(l) For which E°cell = 2.04 V at 298 K. ΔG° for this reaction is

Correct AnswerverifiedShow Answer

Which, if any, of the following metals would be capable of acting as a sacrificial anode when used with iron pipe? E°Fe = −0.44 V; all E° values refer to the M2+/M half-cell reactions.

Correct AnswerverifiedShow Answer

The value of the equilibrium constant for the reaction of nickel(II) ions with cadmium metal is 1.17 × 105. Calculate ΔG° for the reaction at 25°C.

Correct AnswerverifiedShow Answer

A concentration cell consists of two Al/Al3+electrodes. The electrolyte in compartment A is 0.050 M Al(NO3) 3 and in compartment B is 1.25 M Al(NO3) 3. What is the voltage of the cell at 25°C?

Correct AnswerverifiedShow Answer

In the electrolysis of aqueous sodium sulfate at electrodes of platinum, predict the products of the cell reaction.

Correct AnswerverifiedE

A voltaic cell prepared using aluminum and nickel has the following cell notation. Al(s) | Al3+(aq) || Ni2+(aq) | Ni(s) Which of the following reactions occurs at the anode?

Correct AnswerverifiedShow Answer

A voltaic cell is prepared using copper and silver. Its cell notation is shown below. Cu(s) | Cu2+(aq) || Ag+(aq) | Ag(s) Which of the following processes occurs at the cathode?

Correct AnswerverifiedShow Answer

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be __________. I2(s) + HNO3(aq) → HIO3(aq) + NO2(g) + H2O(l)

Correct AnswerverifiedShow Answer

A voltaic cell is based on the following two half-reactions: Ni+2(aq) + 2e− → Ni(s) E° = −0.25 V Cr+3(aq) + 3e- → Cr(s) E° = -0.74 V Sketch the cell and then select the correct statement about it.

Correct AnswerverifiedShow Answer

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be Al(s) + HSO4(aq) + OH−(aq) → Al2O3(s) + S2−(aq) + H2O(l)

Correct AnswerverifiedShow Answer

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be I−(aq) + NO3−(aq) → NO(g) + I2(s) (acidic solution)

Correct AnswerverifiedShow Answer

In the shorthand notation for cells, a double vertical line is used to separate the reduced and oxidized forms of a redox couple.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°cell = 0.30 V Sn2+(aq) + Fe(s) ⇄ Sn(s) + Fe2+(aq)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedA

Consider the following balanced redox reaction Mn2+(aq) + S2O82−(aq) + 2H2O(l) → MnO2(s) + 4H(aq) + 2SO42−(aq) Which of the following statements is true?

Correct AnswerverifiedShow Answer

Consider the reaction of iodine with manganese dioxide 3I2(s) + 2MnO2(s) + 8OH-(aq) ⇄ 6I−(aq) + 2MnO4(aq) + 4H2O(l) The equilibrium constant for the overall reaction is 8.30 × 10−7. Calculate E°cell for the reaction at 25°C.

Correct AnswerverifiedD

Correct Answer
verified

Calculate ΔG° for the reaction of iron(II) ions with one mole of permanganate ions. MnO₄⁻(aq) + 8H⁺(aq) + 5e⁻ ⇄ Mn²⁺(aq) + 4H₂O(l) E° = 1.51 V Fe³⁺(aq) + e⁻ ⇄ Fe²⁺(aq) E°= 0.77 V

Correct Answer
verified

A voltaic cell can be prepared from copper and tin. What is the E°_cell for the cell that forms from the following half-reactions? Cu²⁺(aq) + 2e⁻⇄ Cu(s) E° = 0.34 V Sn⁴⁺(aq) + 2e⁻ ⇄ Sn²⁺(aq) E° = 0.13 V

Correct Answer
verified

Consider the reaction in the lead-acid cell Pb(s) + PbO₂(s) + 2H₂SO₄(aq) → 2PbSO₄(aq) + 2H₂O(l) For which E°_cell = 2.04 V at 298 K. ΔG° for this reaction is

Correct Answer
verified

Which, if any, of the following metals would be capable of acting as a sacrificial anode when used with iron pipe? E°_Fe = −0.44 V; all E° values refer to the M²⁺/M half-cell reactions.

Correct Answer
verified

The value of the equilibrium constant for the reaction of nickel(II) ions with cadmium metal is 1.17 × 10⁵. Calculate ΔG° for the reaction at 25°C.

Correct Answer
verified

A concentration cell consists of two Al/Al³⁺electrodes. The electrolyte in compartment A is 0.050 M Al(NO₃) ₃and in compartment B is 1.25 M Al(NO₃) ₃. What is the voltage of the cell at 25°C?

Correct Answer
verified

Correct Answer
verified
E

A voltaic cell prepared using aluminum and nickel has the following cell notation. Al(s) | Al³⁺(aq) || Ni²⁺(aq) | Ni(s) Which of the following reactions occurs at the anode?

Correct Answer
verified

A voltaic cell is prepared using copper and silver. Its cell notation is shown below. Cu(s) | Cu²⁺(aq) || Ag⁺(aq) | Ag(s) Which of the following processes occurs at the cathode?

Correct Answer
verified

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be __________. I₂(s) + HNO₃(aq) → HIO₃(aq) + NO₂(g) + H₂O(l)

Correct Answer
verified

A voltaic cell is based on the following two half-reactions: Ni⁺²(aq) + 2e⁻ → Ni(s) E° = −0.25 V Cr⁺³(aq) + 3e^- → Cr(s) E° = -0.74 V Sketch the cell and then select the correct statement about it.

Correct Answer
verified

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be Al(s) + HSO₄(aq) + OH⁻(aq) → Al₂O₃(s) + S²⁻(aq) + H₂O(l)

Correct Answer
verified

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the iodide ion will be I⁻(aq) + NO₃⁻(aq) → NO(g) + I₂(s) (acidic solution)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°_cell = 0.30 V Sn²⁺(aq) + Fe(s) ⇄ Sn(s) + Fe²⁺(aq)

Correct Answer
verified

Correct Answer
verified
A

Consider the following balanced redox reaction Mn²⁺(aq) + S₂O₈²⁻(aq) + 2H₂O(l) → MnO₂(s) + 4H(aq) + 2SO₄²⁻(aq) Which of the following statements is true?

Correct Answer
verified

Consider the reaction of iodine with manganese dioxide 3I₂(s) + 2MnO₂(s) + 8OH^-(aq) ⇄ 6I⁻(aq) + 2MnO₄(aq) + 4H₂O(l) The equilibrium constant for the overall reaction is 8.30 × 10⁻⁷. Calculate E°_cell for the reaction at 25°C.

Correct Answer
verified
D