Deck 18: Electrochemistry

Question 1

How many electrons are transferred in the following reaction when it is balanced in acidic solution? SO₃^2-(aq)+ MnO₄^-(aq) $\to$ SO₄^2-(aq)+ Mn²⁺(aq)

A)6
B)2
C)10
D)5
E)3

Answer 1

10

Question 2

When the equation for the following reaction in basic solution is balanced,what is the sum of the coefficients? MnO₂ + HO₂^- $\to$ MnO₄^-

A)11
B)31
C)14
D)9
E)18

Answer 2

9

Question 3

When the equation Cl₂ $\to$ Cl^- + ClO₃^- (basic solution)is balanced using the smallest whole-number coefficients,the coefficient of OH^- is:

A)1
B)12
C)3
D)4
E)6

Answer 3

6

Question 4

The following reaction occurs in aqueous acid solution:
NO₃^- + I^- $\to$ IO₃^- + NO₂

-In the balanced equation the coefficient of NO₃^- is:

A)2
B)3
C)4
D)5
E)6

Question 5

When the following reaction is balanced in acidic solution,what is the coefficient of I₂? IO₃^- + I^- $\to$ I₂

A)1
B)2
C)3
D)4
E)none of these

Question 6

The following unbalanced equation represents a reaction that occurs in basic solution: MnO₄^2- + C₂O₄^2- $\to$ MnO₂ + CO₃^2-
How many moles of MnO₄^2- are required to produce 1 mole of CO₃^2-?

A)4
B)3
C)2
D)1
E)none of these

Question 7

When the equation for the following reaction in basic solution is balanced,what is the sum of the coefficients? MnO₄^-(aq)+ CN^-(aq) $\to$ MnO₂(s)+ CNO^-(aq)

A)13
B)8
C)10
D)20
E)11

Question 8

Balance the following oxidation-reduction reaction using the half-reaction method. Cr₂O₇^2- + I₂ $\to$ Cr³⁺ + IO₃^-
In the balanced equation,the coefficient of water is:

A)4
B)17
C)11
D)7
E)6

Question 9

The following reaction occurs in aqueous acid solution:
NO₃^- + I^- $\to$ IO₃^- + NO₂

-In the balanced equation the coefficient of water is:

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

Question 10

What is the oxidation state of Hg in Hg₂Cl₂?

A)+2
B)-1
C)-2
D)+1
E)0

Question 11

Consider a galvanic cell based in the reaction Fe²⁺ + Cr₂O₇^2- $\to$ Fe³⁺ + Cr³⁺ in acidic solution.

-What is the coefficient of Fe³⁺ in the balanced equation?

A)6
B)2
C)3
D)4
E)none of these

Question 12

The reaction below occurs in basic solution.In the balanced equation,what is the sum of the coefficients? Zn + NO₃^- $\to$ Zn(OH)₄^2- + NH₃

A)12
B)15
C)19
D)23
E)27

Question 13

Ammonium metavandate reacts with sulfur dioxide in acidic solution as follows (hydrogen ions and H₂O omitted): xVO₃^- + ySO₂ $\to$ xVO²⁺ + ySO₄^2-
The ratio x : y is

A)1 : 1
B)1 : 2
C)2 : 1
D)1 : 3
E)3 : 1

Question 14

How many electrons are transferred in the following reaction?

A)0
B)1
C)2
D)4
E)not enough information given

Question 15

The following reaction occurs in basic solution: Ag⁺ + Cu $\to$ Ag + Cu²⁺ When the equation is balanced,the sum of the coefficients is:

A)4
B)5
C)6
D)7
E)none of the above

Question 16

For the reaction of sodium bromide with chlorine gas to form sodium chloride and bromine,the appropriate half-reactions are (ox = oxidation and re = reduction):

A)ox: Cl₂ + 2e^- $\to$ 2Cl^-;re: 2Br^- $\to$ Br₂ + 2e^-
B)ox: 2Br^- $\to$ Br₂ + 2e^-;re: Cl₂ + 2e^- $\to$ 2Cl^-
C)ox: Cl + e^- $\to$ Cl^-; re: Br $\to$ Br^- + e^-
D)ox: Br + 2e^- $\to$ Br^2-;re: 2Cl^- $\to$ Cl₂ + 2e^-
E)ox: 2Na⁺ + 2e^- $\to$ 2Na;re: 2Cl^- $\to$ Cl₂ + 2e^-

Question 17

The following questions refer to a galvanic cell that utilizes the following reaction (unbalanced): (AuCl₄)^-(aq)+ Cu(s) $\to$ Au(s)+ Cl^-(aq) + Cu²⁺(aq)
Determine the number of electrons transferred during the reaction (when balanced).

A)2
B)3
C)4
D)6
E)9

Question 18

The following reaction occurs in basic solution: F₂ + H₂O $\to$ O₂ + F^-
When the equation is balanced,the sum of the coefficients is:

A)10
B)11
C)12
D)13
E)none of these

Question 19

Given the following reaction in acidic media: Fe²⁺ + Cr₂O₇^2- $\to$ Fe³⁺ + Cr³⁺
Answer the following question: The coefficient for water in the balanced reaction is:

A)1
B)3
C)5
D)7
E)none of these

Question 20

How many electrons are transferred in the following reaction? 2ClO₃^- + 12H⁺ + 10I^- $\to$ 5I₂ + Cl₂ + 6H₂O

A)12
B)5
C)2
D)30
E)10

Question 21

What is the value of Q,the reaction quotient,for this cell reaction?

A)6.7 $\times$ 10⁴⁰
B)1.5 $\times$ 10^-41
C)1.5 $\times$ 10^-4
D)6.7 $\times$ 10³
E)none of these

Question 22

The anode in a voltaic cell and in an electrolytic cell is

A)positive in both cells
B)the site of oxidation and of reduction,respectively
C)the site of reduction and of oxidation,respectively
D)the site of oxidation in both cells
E)the site of reduction in both cells

Question 23

Which energy conversion shown below takes place in a galvanic cell?

A)electrical to chemical
B)chemical to electrical
C)mechanical to chemical
D)chemical to mechanical
E)mechanical to electrical

Question 24

A strip of copper is placed in a 1 M solution of copper nitrate and a strip of silver is placed in a 1 M solution of silver nitrate.The two metal strips are connected to a voltmeter by wires and a salt bridge connects the solutions.The following standard reduction potentials apply: Ag⁺(aq)+ e^- $\to$ Ag(s)
$\varepsilon$ ^$\circ$ =+0.80 V
Cu²⁺(aq)+ 2e^- $\to$ Cu(s)
$\varepsilon$ ^$\circ$ = +0.34 V
Which of the following statements is false?

A)Electrons flow in the external circuit from the copper electrode to the silver electrode.
B)The silver electrode increases in mass as the cell operates.
C)There is a net general movement of silver ions through the salt bridge to the copper half-cell.
D)Negative ions pass through the salt bridge from the silver half-cell to the copper half-cell.
E)Some positive copper ions pass through the salt bridge from the copper half-cell to the silver half-cell.

Question 25

Refer to the galvanic cell below (the contents of each half-cell are written beneath each compartment): 0.10 M MnO₄^- 0.40 M Cr³⁺
0.20 M Mn²⁺ 0.30 M Cr₂O₇^2-
0.010 M H⁺ 0.010 M H⁺
The standard reduction potentials are as follows:
MnO₄^- + 8H⁺ + 5e^- $\to$ Mn²⁺ + 4H₂O, $\varepsilon$ ^$\circ$ = 1.51 V
Cr₂O₇^2- + 14H⁺ + 6e^- $\to$ 2Cr³⁺ + 7H₂O, $\varepsilon$ ^$\circ$ =1.33 V

-When current is allowed to flow,which species is oxidized?

A)Cr₂O₇^2-
B)Cr³⁺
C)MnO₄^-
D)Mn²⁺
E)H⁺

Question 26

Which of the following reactions is possible at the anode of a galvanic cell?

A)Zn $\to$ Zn²⁺ + 2e^-
B)Zn²⁺ + 2e^- $\to$ Zn
C)Zn²⁺ + Cu $\to$ Zn + Cu²⁺
D)Zn + Cu²⁺ $\to$ Zn²⁺ + Cu
E)two of these

Question 27

Which of the following is the best reducing agent? Cl₂ + 2e^- $\to$ 2Cl^-
$\varepsilon$ ^$\circ$ = 1.36 V
Mg²⁺ + 2e^- $\to$ Mg
$\varepsilon$ ^$\circ$ = -2.37 V
2H⁺ + 2e^- $\to$ H₂
$\varepsilon$ ^$\circ$ = 0.00 V

A)Cl₂
B)H₂
C)Mg
D)Mg²⁺
E)Cl^-

Question 28

What is the oxidation state of Cr in Cr₂O₇^2-?

A)+7
B)+6
C)+12
D)-1
E)-2

Question 29

Consider a galvanic cell based in the reaction Fe²⁺ + Cr₂O₇^2- $\to$ Fe³⁺ + Cr³⁺ in acidic solution.

-Calculate the voltage of the standard cell carrying out this reaction.

A)0
B)0.21 V
C)-0.21 V
D)0.56 V
E)-0.56 V

Question 30

Which of the following is true for the cell shown here? Zn(s)| Zn²⁺(aq)|| Cr³⁺(aq)| Cr(s)

A)The electrons flow from the cathode to the anode.
B)The electrons flow from the zinc to the chromium.
C)The electrons flow from the chromium to the zinc.
D)The chromium is oxidized.
E)The zinc is reduced.

Question 31

Consider the galvanic cell shown below (the contents of each half-cell are written beneath each compartment): 0.50 M Br₂ 0.20 M Cr³⁺ 0.10 M Br^-
The standard reduction potentials are as follows:
Cr³⁺(aq)+ 3e^- $\to$ Cr(s) $\varepsilon$ ^$\circ$ =-0.73 V
Br₂(aq)+ 2e^- $\to$ 2Br^-(aq) $\varepsilon$ ^$\circ$ = +1.09 V
Which of the following statements about this cell is false?

A)This is a galvanic cell.
B)Electrons flow from the Pt electrode to the Cr electrode.
C)Reduction occurs at the Pt electrode.
D)The cell is not at standard conditions.
E)To complete the circuit,cations migrate into the left half-cell and anions migrate into the right half-cell from the salt bridge.

Question 32

Which statement is always true of the cathode in an electrochemical cell?

A)It is considered the "negative" electrode.
B)It is considered the "positive" electrode.
C)Reduction occurs here.
D)Metal is plated out here.
E)Negative ions flow toward the cathode.

Question 33

Consider the galvanic cell shown below (the contents of each half-cell are written beneath each compartment): 0.50 M Br₂ 0.20 M Cr³⁺ 0.10 M Br^-
The standard reduction potentials are as follows:
Cr³⁺(aq)+ 3e^- $\to$ Cr(s) $\varepsilon$ ^$\circ$ =-0.727 V
Br₂(aq)+ 2e^- $\to$ 2Br^-(aq) $\varepsilon$ ^$\circ$ = +1.090 V
What is $\varepsilon$ ^$\circ$ for this cell?

A)1.817 V
B)0.363 V
C)-0.363 V
D)4.724 V
E)1.316 V

Question 34

Which of the following is the strongest oxidizing agent? MnO₄^- + 4H⁺ + 3e^- $\to$ MnO₂ + 2H₂O
$\varepsilon$ ^$\circ$ = 1.68 V
I₂ + 2e^- $\to$ 2I^-
$\varepsilon$ ^$\circ$ = 0.54 V
Zn²⁺ + 2e^- $\to$ Zn
$\varepsilon$ ^$\circ$ =-0.76 V

A)MnO₄^-
B)I₂
C)Zn²⁺
D)Zn
E)MnO₂

Question 35

Refer to the galvanic cell below (the contents of each half-cell are written beneath each compartment): 0.10 M MnO₄^- 0.40 M Cr³⁺ 0.20 M Mn²⁺ 0.30 M Cr₂O₇^2-
0.010 M H⁺ 0.010 M H⁺
The standard reduction potentials are as follows:
MnO₄^- + 8H⁺ + 5e^- $\to$ Mn²⁺ + 4H₂O, $\varepsilon$ ^$\circ$ = 1.506 V
Cr₂O₇^2- + 14H⁺ + 6e^- $\to$ 2Cr³⁺ + 7H₂O, $\varepsilon$ ^$\circ$ = 1.330 V
What is the value of $\varepsilon$ ^$\circ$ _cell?

A)-0.176
B)2.836
C)0.176
D)0.676
E)6.200

Question 36

In which direction do electrons flow in the external circuit?

A)left to right
B)right to left
C)no current flows;the cell is at equilibrium
D)cannot be determined.
E)none of these

Question 37

Which metal,Al or Ni could reduce Zn²⁺ to Zn(s)if placed in a Zn²⁺(aq)solution? Zn²⁺ + 2e^- $\to$ Zn
$\varepsilon$ ^$\circ$ = -0.76 V
Al³⁺ + 3e^- $\to$ Al
$\varepsilon$ ^$\circ$ = -1.66 V
Ni²⁺ + 2e^- $\to$ Ni
$\varepsilon$ ^$\circ$ =-0.23 V

A)Al
B)Ni
C)Both Al and Ni would work.
D)Neither Al nor Ni would work.
E)Cannot be determined.

Question 38

You are told that metal X is a better reducing agent than metal Y.This must mean that:

A)X⁺ is a better oxidizing agent than Y⁺.
B)X⁺ is a better reducing agent than Y⁺.
C)Y is a better oxidizing agent than X.
D)Y⁺ is a better reducing agent than X⁺.
E)Y⁺ is a better oxidizing agent than X⁺.

Question 39

Refer to the galvanic cell below (the contents of each half-cell are written beneath each compartment): 0.10 M MnO₄^- 0.40 M Cr³⁺
0.20 M Mn²⁺ 0.30 M Cr₂O₇^2-
0.010 M H⁺ 0.010 M H⁺
The standard reduction potentials are as follows:
MnO₄^- + 8H⁺ + 5e^- $\to$ Mn²⁺ + 4H₂O, $\varepsilon$ ^$\circ$ = 1.51 V
Cr₂O₇^2- + 14H⁺ + 6e^- $\to$ 2Cr³⁺ + 7H₂O, $\varepsilon$ ^$\circ$ =1.33 V

-When current is allowed to flow,which species is reduced?

A)Cr₂O₇^2-
B)Cr³⁺
C)MnO₄^-
D)Mn²⁺
E)H⁺

Question 40

Which of the following species cannot function as an oxidizing agent?

A)S(s)
B)NO₃^-(aq)
C)Cr₂O₇^2-(aq)
D)I^-(aq)
E)MnO₄^-(aq)

Question 41

Determine the standard potential, $\varepsilon$ ^$\circ$ ,of a cell that employs the reaction: Fe + Cu²⁺ $\to$ Cu + Fe²⁺.
Reaction
$\varepsilon$ ^$\circ$ (volts) -0.441 +0.340

A)-0.101
B)-0.781
C)0.101
D)0.781
E)-0.202

Question 42

In the balanced cell reaction,what is the stoichiometric coefficient for H⁺?

A)5
B)6
C)30
D)22
E)2

Question 43

The following question refers to the following system: 3Ag(s)+ NO₃^-(aq)+ 4H⁺(aq) $\to$ 3Ag⁺(aq)+ NO(g)+ 2H₂O(l)
Anode reaction:
Ag $\to$ Ag⁺(aq)+ e^-
$\varepsilon$ ^$\circ$ = -0.7990 V
Cathode reaction:
NO₃^-(aq)+ 4H⁺(aq)+ 3e^- $\to$ NO(g)+ 2H₂O(l)
$\varepsilon$ ^$\circ$ = 0.9644 V
Determine the standard cell potential.

A)-1.7634 V
B)0.1654 V
C)2.0942 V
D)3.5268 V
E)0.5878 V

Question 44

Consider the following electrode potentials: Mg²⁺ + 2e^- \9\to\) Mg
$\varepsilon$ ^$\circ$ = -2.37 V
V²⁺ + 2e^- $\to$ V
$\varepsilon$ ^$\circ$ = -1.19 V
Cu²⁺ + e^- $\to$ Cu⁺
$\varepsilon$ ^$\circ$ = 0.16 V
Which one of the reactions below will proceed spontaneously from left to right?

A)Mg²⁺ + V $\to$ V²⁺ + Mg

B)Mg²⁺ + 2Cu⁺ $\to$ 2Cu²⁺ + Mg

C)V²⁺ + 2Cu⁺ $\to$ V + 2Cu²⁺

D)V + 2Cu²⁺ $\to$ V²⁺ + 2Cu⁺
E)none of these

Question 45

You wish to plate out zinc metal from a zinc nitrate solution.Which metal,Al or Ni,could you place in the solution to accomplish this?

A)Al
B)Ni
C)Both Al and Ni would work.
D)Neither Al nor Ni would work.
E)Cannot be determined.

Question 46

Of Sn²⁺,Ag⁺,and/or Zn²⁺,which could be reduced by Cu?

A)Sn²⁺
B)Ag⁺
C)Zn²⁺
D)Two of them could be reduced by Cu.
E)All of them could be reduced by Cu.

Question 47

Choose the correct statement given the following information:

A)Fe²⁺(aq)is more likely to be oxidized than Fe²⁺ complexed to CN^-.
B)Fe³⁺(aq)is more likely to be reduced than Fe³⁺ complexed to CN^-.
C)Both A and B are true.
D)Complexation of Fe ions with CN^- has no effect on their tendencies to become oxidized or reduced.
E)None of these is true.

Question 48

Which of the following would be the best oxidizing agent?

A)Cl₂
B)Fe
C)Na
D)Na⁺
E)F^-

Question 49

What is the cell reaction for the voltaic cell Cr(s)| Cr³⁺(aq)|| Cl^-(aq)| Cl₂(g)| Pt?

A)Cr(s)+ 2Cl^-(aq) Cl₂(g)+ Cr³⁺(aq)
B)2Cr³⁺(aq)+ 6Cl^-(aq) 2Cr(s)+ 3Cl₂(g)
C)Cr(s)+ 3Cl₂(g) Cr³⁺(s)+ 2Cl^-(aq)
D)2Cr(s)+ 3Cl₂(g) 2Cr³⁺(aq)+ 6Cl^-(aq)
E)none of these

Question 50

How many electrons are transferred in the balanced reaction (i.e. ,what will be the value of n in the Nernst equation)?

A)5
B)6
C)30
D)22
E)2

Question 51

What is the cell potential at 25°C as read on the digital voltmeter?

A)0.18 V
B)2.58 V
C)0.10 V
D)0.59 V
E)0.26 V

Question 52

What is the balanced chemical equation corresponding to the following cell diagram? Na(s)| Na⁺(aq)|| Cu²⁺(aq)| Cu(s)

A)2Na(s)+ 2Na⁺(aq) $\to$ Cu²⁺(aq)+ Cu(s)
B)Cu(s)+ 2Na⁺(aq) $\to$ 2Na(s)+ Cu²⁺(aq)
C)2Na(s)+ Cu(s) $\to$ 2Na⁺(aq)+ Cu²⁺(aq)
D)Cu²⁺(aq)+ Cu(s) $\to$ 2Na(s)+ 2Na⁺(aq)
E)2Na(s)+ Cu²⁺(aq) $\to$ 2Na⁺(aq)+ Cu(s)

Question 53

Consider an electrochemical cell with a zinc electrode immersed in 1.0 M Zn²⁺ and a silver electrode immersed in 1.0 M Ag⁺. Zn²⁺ + 2e^- $\to$ Zn $\varepsilon$ ^$\circ$ = -0.755 V
Ag⁺ + e^- $\to$ Ag $\varepsilon$ ^$\circ$ = 0.800 V
Calculate $\varepsilon$ ^$\circ$ for this cell.

A)0.045 V
B)-0.045 V
C)1.555 V
D)-1.555 V
E)none of these

Question 54

The following question refers to a galvanic cell that utilizes the following reaction (unbalanced): (AuCl₄)^-(aq)+ Cu(s) $\to$ Au(s)+ Cl^-(aq)+ Cu²⁺(aq)
Given the following information,determine the standard cell potential:
Species
Standard Reduction Potential (V)
Au³⁺(aq)
1.4980
Cu²⁺(aq)

A)1.1590 V
B)1.8370 V
C)3.8160 V
D)0.8200 V
E)4.1550 V

Question 55

Which of the following is the best reducing agent?

A)Cl₂
B)H₂
C)Mg
D)Mg²⁺
E)Cl^-

Question 56

Copper will spontaneously reduce which of the following?

A)Fe²⁺ and Ag⁺
B)Fe²⁺
C)Ag⁺
D)Al³⁺
E)Fe²⁺ and Al³⁺

Question 57

The galvanic cell described by Zn(s)| Zn²⁺(aq)| Cu²⁺(aq)| Cu(s)has a standard cell potential of 1.101 volts.Given that Zn(s) $\to$ Zn²⁺(aq)+ 2e^- has an oxidation potential of 0.764 volts,determine the reduction potential for .

A)1.865 V
B)-1.865 V
C)-0.337 V
D)0.337 V
E)none of these

Question 58

A cell is set up with copper and lead electrodes in contact with CuSO₄(aq)and Pb(NO₃)₂(aq),respectively,at 25°C.The standard reduction potentials are: Pb²⁺ + 2e^- $\to$ Pb $\varepsilon$ ^$\circ$ = -0.13 V
Cu²⁺ + 2e^- $\to$ Cu $\varepsilon$ ^$\circ$ = +0.34 V
If the Pb²⁺ and Cu²⁺ are each 1.0 M,the potential of the cell,in volts,is:

A)0.47 V
B)0.92 V
C)0.22 V
D)0.58 V
E)none of these

Question 59

The following has a potential of 0.92 V: If the concentrations of the ions were 1.0 M and the pressure of H₂ were 1.0 atm,then $\varepsilon$ ^$\circ$ for the half-reaction would be

A)-0.92 V
B)-0.46 V
C)0.46 V
D)0.92 V
E)none of these

Question 60

Which of the following cell diagrams represents a galvanic cell? ( $\varepsilon$ ^$\circ$ _red(Sn²⁺/Sn)= -0.138V, $\varepsilon$ ^$\circ$ _red(H⁺/H₂)= 0.00 V)

A)Pt(s),H₂(g)| H⁺(aq)|| Sn²⁺(aq)| Sn(s)
B)Sn(s)| Sn²⁺(aq)|| H⁺(aq)| H₂(g),Pt(s)
C)Sn(s),H₂(g)| H⁺(aq)|| Sn²⁺(aq)| Pt(s)
D)Pt(s)| Sn²⁺(aq)|| H⁺(aq)| H₂(g),Sn(s)
E)Sn(s)| Pt(s)|| H⁺(aq),Sn²⁺(aq)| H₂(g)

Question 61

The following question refers to the following system: 3Ag(s)+ NO₃^-(aq)+ 4H⁺(aq) $\to$ 3Ag⁺(aq)+ NO(g)+ 2H₂O(l)
Anode reaction:
Ag $\to$ Ag⁺(aq)+ 1e^-
$\varepsilon$ ° = -0.7990 V
Cathode reaction:
NO₃^-(aq)+ 4H⁺(aq)+ 3e^- $\to$ NO(g)+ 2H₂O(l)
$\varepsilon$ ° = 0.9636 V
Determine the equilibrium constant at 25°C.

A)
B)
C)
D)
E)3.117

Question 62

For a particular reaction in a galvanic (voltaic)cell $\Delta$ S° is negative.Which of the following statements is true?

A)( $\varepsilon$ ) will increase with an increase in temperature.
B)( $\varepsilon$ ) will decrease with an increase in temperature.
C)( $\varepsilon$ ) will not change when the temperature increases.
D)( $\Delta$ G° > 0) for all temperatures.
E)None of the above statements is true.

Question 63

A fuel cell designed to react grain alcohol with oxygen has the following net reaction: C₂H₅OH(l)+ 3O₂(g) $\to$ 2CO₂(g)+ 3H₂O(l)
The maximum work one mole of alcohol can yield by this process is 1320 kJ.What is the theoretical maximum voltage this cell can achieve?

A)0.760 V
B)1.14 V
C)2.01 V
D)2.28 V
E)13.7 V

Question 64

Consider the following reduction potentials: Cu²⁺ + 2e^- $\to$ Cu $\varepsilon$ ^$\circ$ = 0.342 V
Pb²⁺ + 2e^- $\to$ Pb $\varepsilon$ ^$\circ$ = -0.130 V
For a galvanic cell employing the Cu,Cu²⁺ and Pb,Pb²⁺ couples,calculate the maximum amount of work that would accompany the reaction of one mole of lead under standard conditions.

A)-40.9 kJ
B)-45.5 kJ
C)-91.1 kJ
D)No work can be done.The system is at equilibrium.
E)None of these.

Question 65

Which of the following statements is true concerning the electrochemical cell depicted below? Ca | Ca²⁺(aq)|| K⁺(aq)| K
Ca²⁺(aq)+ 2e^- $\to$ Ca(s); $\varepsilon$ ^$\circ$ = -2.87 V
K⁺(aq)+ e^- $\to$ K(s); $\varepsilon$ ^$\circ$ = -2.93 V

A)The cell reaction is spontaneous with a standard cell potential of 0.06 V.
B)The cell reaction is nonspontaneous with a standard cell potential of -5.80 V.
C)The cell reaction is nonspontaneous with a standard cell potential of -0.06 V.
D)The cell reaction is spontaneous with a standard cell potential of 5.80 V.
E)The cell is at equilibrium.

Question 66

Determine $\Delta$ G° for a cell that utilizes the following reaction: Cl₂(g)+ 2Br^-(aq) $\to$ 2Cl^-(aq)+ Br₂(l)
The standard reduction for the chlorine gas is 1.360 volts and the standard reduction for the bromine liquid is about 1.078 volts.

A)-470 kJ
B)-27.2 kJ
C)-235 kJ
D)-54.4 kJ
E)-23.9 kJ

Question 67

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

A)Co(s)+ 2Ag⁺(aq) $\to$ Co²⁺(aq)+ 2Ag(s)
B)3Sr(s)+ 2Au³⁺(aq) $\to$ 3Sr²⁺ + 2Au(s)
C)3Rb⁺(aq)+ Al(s) $\to$ 3Rb(s)+ Al³⁺(aq)
D)Ba(s)+ 2MnO₂(s)+ 2NH₄⁺(aq) $\to$ Ba²⁺(aq)+ Mn₂O₃(s)+ 2NH₃(aq)+ H₂O(l)
E)Sr(s)+ 2Ag⁺(aq) $\to$ 2Ag(s)+ Sr²⁺(aq)

Question 68

The reduction potentials for Au³⁺ and Ni²⁺ are as follows: Au³⁺ + 3e^- $\to$ Au, $\varepsilon$ ^$\circ$ = +1.50 V
Ni²⁺ + 2e^- $\to$ Ni, $\varepsilon$ ^$\circ$ = -0.229 V
Calculate $\Delta$ G° (at 25°C)for the reaction:
2Au³⁺ + 2Ni $\to$ 3Ni²⁺ + 2Au

A) kJ
B) kJ
C) kJ
D) kJ
E) kJ

Question 69

For a certain reaction, $\Delta$ H° = -74.4 kJ and $\Delta$ S° = -227 J/K.If n = 3,calculate $\varepsilon$ ^$\circ$ for the reaction at 25°C.

A)0.0233 V
B)0.491 V
C)0.277 V
D)0.0700 V
E)0.237 V

Question 70

What is $\Delta$ G° for the following electrochemical equation? ( $\varepsilon$ °_red(Ag⁺/Ag)= 0.800 V, $\varepsilon$ °_red(Cd²⁺/Cd)= -0.403 V) 2Ag(s)+ Cd²⁺(aq) $\to$ 2Ag⁺(aq)+ Cd(s)

A)-232 kJ/mol
B)116 kJ/mol
C)232 kJ/mol
D)464 kJ/mol
E)-464 kJ/mol

Question 71

A common car battery consists of six identical cells,each of which carries out the reaction: Pb + PbO₂ + 2HSO₄^- + 2H⁺ $\to$ 2PbSO₄ + 2H₂O
The value of for such a cell is 2.039 V.Calculate $\Delta$ G° at 25 °C for the reaction.

A)-196.7 kJ
B)-98.37 kJ
C)-393.5 kJ
D)-786.9 kJ
E)-590.2 kJ

Question 72

Under standard conditions,which of the following operations results in a spontaneous chemical reaction taking place?

A)A piece of aluminum metal is placed in an aqueous solution of potassium nitrate.
B)Iodine crystals are added to an aqueous solution of sodium chloride.
C)A piece of silver metal is placed in an aqueous solutions of copper(II)nitrate.
D)Chlorine gas is bubbled through an aqueous solution of sodium bromide.
E)At least two of the above (A-D)result in a spontaneous chemical reaction.

Question 73

A galvanic cell consists of a left compartment with a tin electrode in contact with 0.1 M Sn(NO₃)₂(aq)and a right compartment with a lead electrode in contact with 1 $\times$ 10^-3 M Pb(NO₃)₂(aq).The relevant reduction potentials are: Pb²⁺ + 2e^- $\to$ Pb
$\varepsilon$ ° = -0.13 V
Sn²⁺ + 2e^- $\to$ Sn
$\varepsilon$ ° = -0.14 V
When this cell is allowed to discharge spontaneously at 25°C,which of the following statements is true?

A)Electrons will flow from left to right through the wire.
B)Pb²⁺ ions will be reduced to Pb metal.
C)The concentration of Sn²⁺ ions in the left compartment will increase.
D)The tin electrode will be the cathode.
E)No noticeable change will occur,because the cell is at equilibrium.

Question 74

Tables of standard reduction potentials are usually given at 25°C. $\varepsilon$ ^$\circ$ depends on temperature.Which of the following equations describes the temperature dependence of $\varepsilon$ ^$\circ$ ?

A)
B)
C)
D)
E)none of these

Question 75

For a reaction in a voltaic cell both $\Delta$ H° and $\Delta$ S° are positive.Which of the following statements is true?

A)( $\varepsilon$ ^$\circ$ _cell) will increase with an increase in temperature.
B)( $\varepsilon$ ^$\circ$ _cell) will decrease with an increase in temperature.
C)( $\varepsilon$ ^$\circ$ _cell) will not change when the temperature increases.
D)( $\Delta$ G° > 0) for all temperatures.
E)None of the above statements is true.

Question 76

Consider an electrochemical cell with a zinc electrode immersed in 1.0 M Zn²⁺ and a nickel electrode immersed in 0.10 M Ni²⁺.
Zn²⁺ + 2e- $\to$ Zn
$\varepsilon$ ° = -0.76 V
Ni²⁺ + 2e- $\to$ Ni
$\varepsilon$ ° = -0.23 V

-Calculate the concentration of Ni²⁺ if the cell is allowed to run to equilibrium at 25°C.

A)1.10 M
B)0.20 M
C)0.10 M
D)0 M
E)none of these

Question 77

Consider an electrochemical cell with a zinc electrode immersed in 1.0 M Zn²⁺ and a nickel electrode immersed in 0.10 M Ni²⁺.
Zn²⁺ + 2e- $\to$ Zn
$\varepsilon$ ° = -0.76 V
Ni²⁺ + 2e- $\to$ Ni
$\varepsilon$ ° = -0.23 V

-Calculate $\varepsilon$ at 25°C for the cell shown below,given the following data:



K_sp for AgCl = 1.6 $\times$ 10^-10

A)0.83 V
B)0.54 V
C)1.01 V
D)2.98 V
E)cannot be determined from the data given

Question 78

What is $\varepsilon$ ^$\circ$ _cell for the following electrochemical equation? ( $\varepsilon$ ^$\circ$ _red(Li⁺/Li)= -3.04 V $\varepsilon$ ^$\circ$ _red(Cu²⁺/Cu)= 0.342 V) 2Li(s)+ Cu²⁺(aq) $\to$ 2Li⁺(aq)+ Cu(s)

A)-5.738 V
B)6.422 V
C)3.382 V
D)-3.382 V
E)-6.422 V

Question 79

Which of the following statements is true concerning the electrochemical cell depicted below? Mg | Mg²⁺(aq)|| Cu²⁺(aq)| Cu
Mg²⁺(aq)+ 2e^- $\to$ Mg(s); -2.38 V
Cu²⁺(aq)+ 2e^- $\to$ Cu(s); 0.34 V

A)The cell reaction is spontaneous with a standard cell potential of 2.72 V.
B)The cell reaction is spontaneous with a standard cell potential of 2.04 V.
C)The cell reaction is nonspontaneous with a standard cell potential of -2.72 V.
D)The cell reaction is nonspontaneous with a standard cell potential of -2.04 V.
E)The cell is at equilibrium.

Question 80

Given: 2H⁺(aq)+ 2e^- $\to$ H₂(g);0.00 V
K⁺(aq)+ e^- $\to$ K(s);-2.93 V
F₂(g)+ 2e^- $\to$ 2F^-(aq);2.87 V
Al³⁺(aq)+ 3e^- $\to$ Al(s);-1.66 V
Pb²⁺(aq)+ 2e^- $\to$ Pb(s);-0.13 V
Under standard-state conditions,which is the strongest reducing agent?

A)H⁺
B)K
C)F^-
D)Al³⁺
E)Pb²⁺