Question 1

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Zn2+,Fe3+,Mg2+,Br-,I-

Accepted Answer

A)  Zn2+ 
B)  Mg2+ 
C)  Br- 
D)  Fe3+ 
E)  I- 
A)  Zn2+ 
B)  Mg2+ 
C)  Br- 
D)  Fe3+ 
E)  I-

Question 2

Which of the following reactions would have the smallest value of K at 298 K?

Accepted Answer

A)  A + B → C; E°cell = +1.22 V 
B)  A + 2 B → C; E°cell = +0.98 V 
C)  A + B → 2 C; E°cell = -0.030 V 
D)  A + B → 3 C; E°cell = +0.15 V 
E)  More information is needed to determine. 
A)  A + B → C; E°cell = +1.22 V 
B)  A + 2 B → C; E°cell = +0.98 V 
C)  A + B → 2 C; E°cell = -0.030 V 
D)  A + B → 3 C; E°cell = +0.15 V 
E)  More information is needed to determine.

Question 3

For the galvanic cell reaction,expressed below using shorthand notation,what half-reaction occurs at the cathode? Zn(s)∣ Zn2+(aq)∣∣ Ni2+(aq)∣ Ni(s)

Accepted Answer

A)  Zn(s) → Zn2+(aq) + 2 e- 
B)  Zn2+(aq) + 2 e- → Zn(s) 
C)  Ni(s) → Ni2+(aq) + 2 e- 
D)  Ni2+(aq) + 2 e- → Ni(s) 
A)  Zn(s) → Zn2+(aq) + 2 e- 
B)  Zn2+(aq) + 2 e- → Zn(s) 
C)  Ni(s) → Ni2+(aq) + 2 e- 
D)  Ni2+(aq) + 2 e- → Ni(s)

Question 4

What element is being oxidized in the following redox reaction? Cr(OH)4-(aq)+ ClO-(aq)→ CrO42-(aq)+ Cl-(aq)

Accepted Answer

A)  Cr 
B)  O 
C)  H 
D)  Cl 
A)  Cr 
B)  O 
C)  H 
D)  Cl

Question 5

In an electrolytic cell,the anode is defined as

Accepted Answer

A)  a metal contact. 
B)  the more positively charged electrode. 
C)  the positive terminal of the power source. 
D)  the more negatively charged electrode. 
E)  the negative terminal of the power source. 
A)  a metal contact. 
B)  the more positively charged electrode. 
C)  the positive terminal of the power source. 
D)  the more negatively charged electrode. 
E)  the negative terminal of the power source.

Question 6

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Na+,Ca2+,Cl⁻,Br⁻,F⁻

Accepted Answer

A)  Na+ 
B)  Cl- 
C)  Ca2+ 
D)  Br- 
E)  F- 
A)  Na+ 
B)  Cl- 
C)  Ca2+ 
D)  Br- 
E)  F-

Question 7

What statement is NOT true about standard electrode potentials?

Accepted Answer

A)  E°cell is positive for spontaneous reactions. 
B)  Electrons will flow from more negative electrode to more positive electrode. 
C)  The electrode potential of the standard hydrogen electrode is exactly zero. 
D)  E°cell is the difference in voltage between the anode and the cathode. 
E)  The electrode in any half-cell with a greater tendency to undergo reduction is positively charged relative to the standard hydrogen electrode and therefore has a positive E°. 
A)  E°cell is positive for spontaneous reactions. 
B)  Electrons will flow from more negative electrode to more positive electrode. 
C)  The electrode potential of the standard hydrogen electrode is exactly zero. 
D)  E°cell is the difference in voltage between the anode and the cathode. 
E)  The electrode in any half-cell with a greater tendency to undergo reduction is positively charged relative to the standard hydrogen electrode and therefore has a positive E°.

Question 8

In a voltaic cell,the anode is defined as

Accepted Answer

A)  a metal contact. 
B)  the more positively charged electrode. 
C)  the positive terminal of the power source. 
D)  the more negatively charged electrode. 
E)  the negative terminal of the power source. 
A)  a metal contact. 
B)  the more positively charged electrode. 
C)  the positive terminal of the power source. 
D)  the more negatively charged electrode. 
E)  the negative terminal of the power source.

Question 9

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Fe(s)∣ Fe3+(aq,0.0011 M)   Fe3+(aq,2.33 M)∣ Fe(s)

Accepted Answer

A)  +0.066 V 
B)  -0.036 V 
C)  0.00 V 
D)  -0.099 V 
E)  +0.20 V 
A)  +0.066 V 
B)  -0.036 V 
C)  0.00 V 
D)  -0.099 V 
E)  +0.20 V

Question 10

What element is being reduced in the following redox reaction? Cr(OH)4⁻(aq)+ ClO⁻(aq)→ CrO42-(aq)+ Cl⁻(aq)

Accepted Answer

A)  Cr 
B)  O 
C)  H 
D)  Cl 
A)  Cr 
B)  O 
C)  H 
D)  Cl

Question 11

Sketch a voltaic cell that contains the following half reactions and label all relevant components.
Zn2+(aq)+ 2e⁻ → Zn(s)E°= -0.76 V
Cu2+(aq)+ 2e⁻ → Cu(s)E°= +0.34 V

Accepted Answer

The sketch should be

Question 12

In a nickel-cadmium battery,NiO(OH)is reduced to

Accepted Answer

A)  Ni(OH)4. 
B)  NiO2. 
C)  Ni. 
D)  Ni(OH)2. 
E)  NiOH. 
A)  Ni(OH)4. 
B)  NiO2. 
C)  Ni. 
D)  Ni(OH)2. 
E)  NiOH.

Question 13

Identify the battery type that has a high overcharge tolerance.

Accepted Answer

A)  NiCad 
B)  Li ion 
C)  NiMH 
D)  lead storage 
E)  none of the above 
A)  NiCad 
B)  Li ion 
C)  NiMH 
D)  lead storage 
E)  none of the above

Question 14

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of Pb and HS1U1P1+S1S1P0 in the balanced reaction? 
PbS1U1P12+S1S1P0(aq)+ NHS1U1B14S1U1B0S1U1P1+S1S1P0(aq)? Pb(s)+ NOS1U1B13S1U1B0?(aq)

Accepted Answer

A)  Pb = 1, H? = 8 
B)  Pb = 1, H? = 2 
C)  Pb = 4, H? = 10 
D)  Pb = 2, H? = 3 
E)  Pb = 3, H? = 5 
A)  Pb = 1, H? = 8 
B)  Pb = 1, H? = 2 
C)  Pb = 4, H? = 10 
D)  Pb = 2, H? = 3 
E)  Pb = 3, H? = 5

Question 15

What is the oxidizing agent in the redox reaction represented by the following cell notation? Sn(s)∣ Sn2+(aq)   Ag+(aq)∣ Ag(s)

Accepted Answer

A)  Sn(s) 
B)  Ag+(aq) 
C)  Sn2+(aq) 
D)  Ag(s) 
E)  Pt 
A)  Sn(s) 
B)  Ag+(aq) 
C)  Sn2+(aq) 
D)  Ag(s) 
E)  Pt

Question 16

In a lead-acid storage battery,Pb is oxidized to

Accepted Answer

A)  PbO2. 
B)  PbSO4. 
C)  Pb2O. 
D)  PbO3. 
E)  PbO. 
A)  PbO2. 
B)  PbSO4. 
C)  Pb2O. 
D)  PbO3. 
E)  PbO.

Question 17

Which of the following is the strongest reducing agent?

Accepted Answer

A)  Ba(s) 
B)  Li+(aq) 
C)  Na(s) 
D)  Cr2+(aq) 
E)  Li(s) 
A)  Ba(s) 
B)  Li+(aq) 
C)  Na(s) 
D)  Cr2+(aq) 
E)  Li(s)

Question 18

How many electrons are transferred in the following reaction? (The reaction is unbalanced.) Ni(s)+ Cr3+(aq)→ Cr(s)+ Ni2+(aq)

Accepted Answer

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

Question 19

Consider the galvanic cell,   Which one of the following changes to the cell would cause the cell potential to increase (i.e.,become more positive)?

Accepted Answer

A)  increase the [Zn2+] concentration 
B)  increase the [Pb2+] concentration 
C)  increase the mass of Zn(s) 
D)  decrease the mass of Zn(s) 
A)  increase the [Zn2+] concentration 
B)  increase the [Pb2+] concentration 
C)  increase the mass of Zn(s) 
D)  decrease the mass of Zn(s)

Question 20

What is the reduction half-reaction for the following overall galvanic cell reaction? Co2+(aq)+ 2 Ag(s)→ Co(s)+ 2 Ag+(aq)

Accepted Answer

A)  Ag(s) + e- → Ag+(aq) 
B)  Ag+(aq) + e- → Ag(s) 
C)  Co2+(aq) + 2 e- → Co(s) 
D)  Co2+(aq) + e- → Co(s) 
A)  Ag(s) + e- → Ag+(aq) 
B)  Ag+(aq) + e- → Ag(s) 
C)  Co2+(aq) + 2 e- → Co(s) 
D)  Co2+(aq) + e- → Co(s)

Exam 19: Electrochemistry

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Zn2+,Fe3+,Mg2+,Br-,I-

Which of the following reactions would have the smallest value of K at 298 K?

For the galvanic cell reaction,expressed below using shorthand notation,what half-reaction occurs at the cathode? Zn(s)∣ Zn2+(aq)∣∣ Ni2+(aq)∣ Ni(s)

What element is being oxidized in the following redox reaction? Cr(OH)4-(aq)+ ClO-(aq)→ CrO42-(aq)+ Cl-(aq)

In an electrolytic cell,the anode is defined as

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Na+,Ca2+,Cl⁻,Br⁻,F⁻

What statement is NOT true about standard electrode potentials?

In a voltaic cell,the anode is defined as

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Fe(s)∣ Fe3+(aq,0.0011 M) Fe3+(aq,2.33 M)∣ Fe(s)

What element is being reduced in the following redox reaction? Cr(OH)4⁻(aq)+ ClO⁻(aq)→ CrO42-(aq)+ Cl⁻(aq)

Sketch a voltaic cell that contains the following half reactions and label all relevant components. Zn2+(aq)+ 2e⁻ → Zn(s)E°= -0.76 V Cu2+(aq)+ 2e⁻ → Cu(s)E°= +0.34 V

In a nickel-cadmium battery,NiO(OH)is reduced to

Identify the battery type that has a high overcharge tolerance.

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of Pb and H+ in the balanced reaction? Pb2+(aq)+ NH4+(aq)? Pb(s)+ NO3?(aq)

What is the oxidizing agent in the redox reaction represented by the following cell notation? Sn(s)∣ Sn2+(aq) Ag+(aq)∣ Ag(s)

In a lead-acid storage battery,Pb is oxidized to

Which of the following is the strongest reducing agent?

How many electrons are transferred in the following reaction? (The reaction is unbalanced.) Ni(s)+ Cr3+(aq)→ Cr(s)+ Ni2+(aq)

Consider the galvanic cell, Which one of the following changes to the cell would cause the cell potential to increase (i.e.,become more positive)?

What is the reduction half-reaction for the following overall galvanic cell reaction? Co2+(aq)+ 2 Ag(s)→ Co(s)+ 2 Ag+(aq)

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Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Zn²⁺,Fe³⁺,Mg²⁺,Br^-,I^-

For the galvanic cell reaction,expressed below using shorthand notation,what half-reaction occurs at the cathode? Zn(s)∣ Zn²⁺(aq)∣∣ Ni²⁺(aq)∣ Ni(s)

What element is being oxidized in the following redox reaction? Cr(OH)₄^-(aq)+ ClO^-(aq)→ CrO₄^2-(aq)+ Cl^-(aq)

Predict the species that will be reduced first if the following mixture of molten salts undergoes electrolysis. Na⁺,Ca²⁺,Cl⁻,Br⁻,F⁻

Calculate the cell potential for the following reaction that takes place in an electrochemical cell at 25°C. Fe(s)∣ Fe³⁺(aq,0.0011 M) Fe³⁺(aq,2.33 M)∣ Fe(s)

What element is being reduced in the following redox reaction? Cr(OH)₄⁻(aq)+ ClO⁻(aq)→ CrO₄^2-(aq)+ Cl⁻(aq)

Sketch a voltaic cell that contains the following half reactions and label all relevant components. Zn²⁺(aq)+ 2e⁻ → Zn(s)E°= -0.76 V Cu²⁺(aq)+ 2e⁻ → Cu(s)E°= +0.34 V

Balance the following redox reaction if it occurs in acidic solution.What are the coefficients in front of Pb and H⁺ in the balanced reaction? Pb²⁺(aq)+ NH₄⁺(aq)? Pb(s)+ NO₃?(aq)

What is the oxidizing agent in the redox reaction represented by the following cell notation? Sn(s)∣ Sn²⁺(aq) Ag⁺(aq)∣ Ag(s)

How many electrons are transferred in the following reaction? (The reaction is unbalanced.) Ni(s)+ Cr³⁺(aq)→ Cr(s)+ Ni²⁺(aq)

What is the reduction half-reaction for the following overall galvanic cell reaction? Co²⁺(aq)+ 2 Ag(s)→ Co(s)+ 2 Ag⁺(aq)