Download 1. When the reaction Cu + HNO3 → Cu2+ + NO + H2O is balanced

1. When the reaction Cu + HNO3 → Cu2+ + NO + H2O is balanced in acidic solution, the
coefficient of H+ is _____.
A) 2
B) 4
C) 3
D) 6
2. The number of moles of hydroxide ions needed to balance the disproportionation
reaction of one mole of bromine to BrO3– and Br– in basic solution is _____.
A) 6
B) 2
C) 3
D) 4
3. The species that is not an oxidizing agent is _____.
A) HNO3
B) BrO3–
C) Cl–
D) MnO4–
4. The correct statement is: _____.
A) Oxidation occurs at the anode
B) Oxidation occurs at the cathode
C) Anions travel to the cathode in an electrochemical cell.
D) Reduction occurs at the anode.
5. The unit of electromotive force is the _____.
A) erg
B) ohm
C) volt
D) ampere
6. In the cell Al|Al(NO3)3 ||AgNO3|Ag, _____. |
A) Aluminum acts as the cathode
B) Silver acts as the cathode
C) Silver is oxidized
D) Aluminum ion gets reduced
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7. The cathode in the Daniell cell is _____.
A) Zn
B) Ag
C) Cu
D) Mg
8. An electrochemical reaction will be spontaneous if _____.
A) ∆G is positive
B) the standard emf of the cell is negative.
C) the standard emf of the cell is positive.
D) resistance is positive.
9. The standard emf of the cell involving Mg/Mg2+ and Cu/Cu2+ half-cell reactions is
_____.
A) 2.03V
B) 1.18V
C) 2.71V
D) 3.71V
10. The process _____ occurs spontaneously under standard state conditions.
A) Cu reduces Mg2+
B) Fe3+ oxidizes I–
C) Fe3+ reduces I2
D) Ag reduces Fe2+
11. The species _____ can oxidize water to oxygen under standard state conditions.
A) Cl–(aq)
B) Cu2+(aq)
C) Pb2+(aq)
D) Cl2(g)
12. The reaction _____ is spontaneous.
A) NO3– oxidizing Mn2+ to MnO4–
B) MnO4– oxidizing Fe to Fe2+
C) Ag reducing Cu2+ to Cu
D) Br2 oxidizing F– to F2
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13. The reaction _____ is spontaneous under standard state conditions.
A) Ca + Cd2+(aq) → Ca2+(aq) + Cd
B) 2 Br–(aq) + Sn2+(aq) → Br2(l) + Sn(s)
C) 2Ag(s) + Ni2+(aq) → 2 Ag+(aq) + Ni(s)
D) Cu2+(aq) + Fe2+(aq) → Cu+(aq) + Fe3+(aq)
14. The pair _____ has the better oxidizing agent listed first.
A) Au3+, Br2
B) H2, Ag+
C) Cr3+, Cd2+
D) O2 in basic media, O2 in acidic media
15. The pair _____ has the better reducing agent listed first.
A) H2, I2
B) Ag, Fe2+
C) Co2+, Brฏ
D) Na, Li
16. The relation connecting ∆Gฐ and Eฐ is _____.
A) ∆Gฐ = nFEฐ
B) Eฐ = ∆Gฐ/RT
C) ∆Gฐ = – RTnFE
D) ∆Gฐ = –nFEฐ
17. The equilibrium constant for the reaction
C is _____.
A) 3.9 × 10–10
B) 8.5 × 1016
C) 2.6 × 1054
D) 6.2 × 1021
at 25 ฐ
18. The equilibrium constant for the reaction
× 1012 at 25ฐC. The value of Eฐ for the above reaction is _____.
A) 0.215 V
B) 0.368 V
C) 0.162 V
D) 1.81V
is 2.69
Page 3
19. The equilibrium constant for the reaction for
ฐC is _____.
A) 5.2 × 109
B) 1.7 × 1011
C) 1.8 × 1018
D) 7.1 × 1014
at 25
20. The reaction _____ has the highest equilibrium constant.
A)
B)
C)
D)
21. The reaction with the largest equilibrium constant at 25 ฐC is _____.
A) Mg(s) + Pb2+(aq) → Mg2+(aq) + Pb(s)
B) Br2(l) + 2I–(aq) → 2 Br–(aq) + I2(s)
C) O2(g) + 4H+(aq) + 4Fe2+(aq) → 2H2O(l) + 4Fe3+(aq)
D) 2 Al(s) + 3I2(s) → 2Al3+(aq) + 6I–(aq)
22. Under standard state conditions, reaction _____ occurs in aqueous solution among the
ions Ce4+, Ce3+, Fe3+, Fe2+.
A) oxidation of Fe2+ by Ce3+
B) reduction of Ce4+ by Fe3+
C) oxidation of Fe2+ by Ce4+
D) reduction of Fe3+ by Ce3+
23. The standard potential for the reduction of Cu+ to Cu is 0.52V. Eฐ at 25 ฐC for 2Cu+(aq)
→ Cu2+(aq) + Cu(s) is _____.
A) 1.04V
B) 0.26V
C) 0.37V
D) 0.86V
24. The equilibrium constant K for the reaction: 2 Cu+(aq)
(The reduction potential for Cu+ to Cu is 0.52V.)
A) 1.8 × 106
B) 1.2 × 10–3
C) 7.2 × 1016
D) 4.6 × 10–9
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Cu2+(aq) + Cu(s) is _____.
25. The Nernst equation for the cell reaction Mg(s) + Sn2+(aq) → Mg2+(aq) + Sn(s) is
_____.
A) E = Eฐ – RT/nF ln [Sn2+]/[Mg2+]
B) E = Eฐ – nF/RT ln [Sn2+]/[Mg2+]
C) E = Eฐ – RT/nF ln [Mg2+]/[Sn2+]
26. The potential of the cell made up of Zn/Zn2+(0.25 M) and Cu/Cu2+(0.15 M) at 25 ฐC is
_____.
A) 1.19 V
B) 1.09 V
C) 1.11 V
D) 1.29 V
27. ∆G for the cell reaction Mg + Sn2+(aq, 0.035M) → Mg2+(aq, 0.045M) + Sn is ––––
kJ/mol.
A) –496
B) –206
C) –406
D) –430
28. The standard potential of the cell consisting of the Zn2+/Zn half-cell and the SHE is
_____.
A) 0.76 V
B) 1.76 V
C) 1.018 V
D) 1.18 V
29. The emf of the cell consisting of the Zn/Zn2+ half-cell with [Zn2+]=0.045 M and the SHE
with P(H2) = 2 atm and [H+]=1.8 M is _____.
A) 0.54 V
B) 0.84 V
C) 0.78 V
D) 0.64 V
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30. The emf of a cell consisting of a Pb/Pb2+(0.01 M) half-cell and a Pt/H+(0.050 M)/H2(g, 1
atm) half-cell is _____.
A) 0.83 V
B) 1.02 V
C) 0.43 V
D) 0.083 V
31. The emf of the concentration cell Mg|Mg2+(0.24 M)|| Mg2+(0.53 M)|Mg is _____.
A) 0 V
B) 0.10 V
C) 0.010 V
D) 1.01 V
32. The standard emf at 25ฐC of the propane fuel cell given that ∆Gฐf for propane = –23.5
kJ/mol is _____. The overall reaction for the fuel cell is:
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)
A) 1.90 V
B) 1.09 V
C) 0.78 V
D) 2.10 V
33. Galvanized iron is steel coated with _____.
A) Sn
B) Zn
C) Hg
D) Na
34. Tarnished silver is coated with _____.
A) Ag2O
B) ZnS
C) AgCl
D) Ag2S
35. The number of grams of Mg that can be produced by supplying 1.0 F to Mg2+ to form
Mg(s) is _____.
A) 24 g
B) 48 g
C) 12 g
D) 1 g
Page 6
36. The mass of barium metal produced by passing a 0.50 A current for 30 min through
molten BaCl2 is _____.
A) 6.4 g
B) 0.64 g
C) 1.6 g
D) 8.1 g
37. The metal that requires the greatest amount of electricity to produce 1 ton of the metal
by electrolysis is _____.
A) sodium
B) magnesium
C) copper
D) aluminum
38. The cost of electricity to produce magnesium by the electrolysis of molten magnesium
chloride is $155 per ton. The cost of producing 10 tons of aluminum is _____.
A) $ 2090
B) $ 365
C) $ 21,800
D) $ 154
39. In the electrolysis of water, _____.
A) hydrogen is liberated at the anode
B) oxygen is liberated at the anode
C) oxygen is liberated at the cathode
D) water is oxidized to hydrogen
40. In the electrolysis of H2O, _____ Faradays of electricity are required to produce 0.076 L
of O2 at 25 ฐC and 755 mmHg.
A) 1.4 F
B) 0.62 F
C) 17 F
D) 0.012 F
41. _____ Faradays are required to liberate 32 g of O2 in the electrolysis of H2O.
A) 2
B) 4
C) 8
D) 6
Page 7
42. The mass of copper produced in 1.00 hr at inert electrodes in a CuBr2 solution by a
current of 4.50 A is _____.
A) 0.340 g
B) 0.0533 g
C) 5.33 g
D) 6.53 g
43. _____ coulombs of electricity are required to deposit 0.67 g of Ag from an aqueous
AgNO3 solution.
A) 1.7 ื 102
B) 4.9 ื 102
C) 9.6 ื 102
D) 6.0 ื 102
44. A constant current flows for 3.75 hrs and liberates 2.00 g of Ag from an AgNO3
solution. The current in amperes is _____.
A) 1.33
B) 0.133
C) 13.3
D) 133
45. A constant current flows through two electrolytic cells connected in series, one
containing AgNO3 and the other containing CuCl2. _____ grams of Cu are deposited in
the second cell if 2.00 g of Ag is deposited in the first.
A) 0.0589
B) 0.295
C) 0.962
D) 0.589
46. The hourly production rate of chlorine in kg from an electrolytic cell using aqueous
NaCl and carrying a current of 1.50 ื 103 A is _______.
A) 1.98 kg
B) 19.8 kg
C) 2.78 kg
D) 27.8 kg
Page 8
47. A current of 1500 A produces chlorine at the rate of 1.64 kg/hr. The anodic efficiency is
_____.
A) 83%
B) 93%
C) 6.3%
D) 53%
48. The number of faradays required to deposit one mole of Cr metal from Cr2O72- is _____.
A) 12
B) 3
C) 6
D) 18
49. The passage of 0.750 A for 25.0 min deposited 0.369 g of a divalent metal. The molar
mass of the metal is _____ g/mol.
A) 63.3
B) 27.1
C) 108
D) 31.7
50. In an electrolysis experiment 1.44 g of Ag was deposited from an aqueous AgNO3
solution, while 0.120 g of the metal X was deposited in another cell that contains
aqueous XCl3 (connected in series with the AgNO3 cell.) The molar mass of X is ––––
g/mol.
A) 63.3
B) 108
C) 27.0
D) 31.8
51. In the electrolysis of water to which a small amount of 0.1 M H2SO4 has been added,
0.845 L of H2 is collected at 25ฐC and 782 mmHg. _____ faradays of electricity passed
through the solution.
A) 0.0711
B) 0.711
C) 0.355
D) 0.0355
Page 9
52. _____ faradays of electricity are required to reduce one mole of MnO4– to Mn2+.
A) 6
B) 5
C) 4
D) 3
53. In the reaction MnO4– + H2O2 → Mn2+ + O2 , _____.
A) 5 moles of H2O2 are oxidized by 2 moles of MnO4–
B) 2 moles of H2O2 are oxidized by 5 moles of MnO4–
C) 3 moles of H2O2 are oxidized by 1 mole of MnO4–
D) 6 moles of H2O2 are oxidized by 4 moles of MnO4–
54. In a titration a 1.0 g sample of plant material containing oxalic acid, H2C2O4, requires
24.0 mL of 0.0100 M KMnO4 to reach the equivalence point. The balanced equation for
the titration is:
16 H+ + 2MnO4ฏ + 5C2O42ฏ → 2Mn2+ + 10CO2 + 8H2O
The percentage of oxalic acid in the sample is _____.
A) 54 %
B) 15 %
C) 5.4 %
D) 1.5 %
55. The correct statement for a cell reaction is _____.
A) ∆E > 0, ∆G < 0, spontaneous
B) ∆E > 0, ∆G > 0, nonspontaneous
C) ∆E < 0, ∆G < 0, spontaneous
D) ∆E < 0, ∆G = 0
56. The solubility product of AgBr is _____ given:
Ag+(aq) + eฏ→ Ag(s) Eฐ=0.80V
AgBr(s) + eฏ → Ag(s) + Brฏ(aq) Eฐ=0.07 V
A) 2.5 × 10–11
B) 5.0 × 10–13
C) 8.5 × 10–12
D) 5.5 × 10–15
Page 10
57. The standard reduction potentials of Ag+(aq) to Ag(s) and AgBr(s) to Ag(s) and Brฏ(aq)
are 0.80 V and 0.07 V, respectively. The standard cell potential for AgBr(s) → Ag+(aq)
+ Brฏ(aq) is _____.
A) 0.87 V
B) 0.73 V
C) –0.87 V
D) –0.73 V
58. The emf of the concentration cell Cu|Cu2+(0.08 M)||Cu2+(1.2 M)|Cu is _____.
A) 0.35 V
B) 0.12 V
C) 0.035 V
D) 0.012 V
59. 1.56g of Mg metal is placed in 100.0 mL of 0.100 M AgNO3. The mass of Mg at
equilibrium will be _____.
A) 1.44 g
B) 1.21 g
C) 1.12 g
D) 1.012 g
60. 1.56 g of Mg is placed in 100.0 mL of 0.100 M AgNO3. The concentration of Mg2+ at
equilibrium is _____.
A) 0.010 M
B) 0.040 M
C) 0.020 M
D) 0.050M
61. An acidified solution of CuSO4 was electrolyzed using copper electrodes. Assuming Cu
is oxidized to Cu2+. What gas is produced at the cathode? And what is the volume of this
gas produced at STP if a constant current of 1.18 A caused the anode to lose 0.584 g
after 1.52 x 103 s?
A) O2, 0.206 L
B) O2, 0.192 L
C) H2, 0.206 L
D) H2, 0.643 L
Page 11
62. In an electrolysis experiment involving Al3+ ions, 60.20 g of Al was produced when a
current of 0.352 A was used. The time necessary, in minutes, to produce this amount of
Al is _____ minutes.
A) 1.06 × 102
B) 3.06 × 104
C) 2.04 × 103
D) 3060
63. The standard cell potential of a fuel cell with the reaction 4NH3(g) + 3O2(g) → 2N2(g) +
6H2O(l) is _____. (Hint: Calculate ∆Gฐ for the reaction.)
A) 2.17 V
B) 0.84 V
C) 1.08 V
D) 1.17 V
64. The addition of a small amount of concentrated NH3 to the zinc electrode of the cell Zn
2+
(0.2 M) || Cu2+ (0.2 M) , _____.
A) increases the emf of the cell
B) decreases the emf of the cell
C) increases the concentration of Zn2+
D) does not change the emf of the cell
65. The addition of a small amount of concentrated NH3 to the copper electrode of the
Daniell cell _____.
A) has no effect on the emf of the cell
B) increases the emf of the cell
C) decreases the emf of the cell
D) increases the reduction of Cu2+
66. The largest increase in the emf of the Daniell cell is caused by: _____.
A) Addition of concentrated NH3 to the copper electrode
B) Addition of concentrated NH3 to the zinc electrode
C) Addition of concentrated NH3 to both electrodes
D) No addition of NH3
Page 12
67. In an electrolysis experiment, a certain quantity of electricity deposits 2.64 g of Ag from
a silver solution and 1.61 of Au from a gold solution. The cells are in series. The
oxidation state of the gold in the solution used is _____.
A) 1
B) 2
C) 4
D) 3
68. The standard reduction potentials of Hg2+/Hg22+ and Hg22+/Hg(l) electrodes are 0.92 and
0.85 V, respectively. The free energy change for the reaction Hg22+(aq) → Hg2+(aq) +
Hg is ____ kJ/mol.
A) 6.8
B) 68
C) 14
D) 7.5
69. 300.0 mL of an aqueous NaCl solution was electrolyzed for 6.00 min. The pH of the
final solution was found to be 12.24. The average current passed through the solution is
_____.
A) 14 A
B) 4.0 A
C) 28 A
D) 1.4 A
70. The time needed to obtain 1.00 kg of Cu from a CuSO4 solution at a current of 18.9 A is
_____.
A) 7.21 hrs
B) 14.4 hrs
C) 44.4 hrs
D) 0.822 hr
71. An aqueous solution of a platinum salt was electrolyzed by a current of 2.5 A for 2.00
hrs. As a result 9.09 g of metallic platinum was deposited. The charge on the platinum
ion is _____.
A) +2
B) +4
C) +3
D) +1
Page 13
72. The standard emf of a cell containing standard cadmium and magnesium electrodes is
_____.
A) 1.97 V
B) 1.18 V
C) 2.37 V
D) 2.02 V
73. A current of 6.00 A passes through an electrolytic cell containing dilute H2SO4 for 3.40
hrs. The volume of O2 generated at the anode at STP was _____.
A) 4.26 L
B) 2.46 L
C) 1.64 L
D) 6.42 L
74. A silver rod and a SHE are dipped into a saturated aqueous solution of Ag2C2O4 at 25ฐC.
The measured potential difference between the Ag rod and the SHE is 0.589 V. The
solubility product of silver oxalate is _____.
A) 9.8 × 10–12
B) 6.2 × 10–8
C) 1.5 × 10–16
D) 2.7 × 10–14
75. The standard reduction potential of the electrode Zn(OH)42?(aq) +2eฏ → Zn(s) + 4OHฏ
(aq) is –1.36 V. The formation constant of Zn(OH) 42– is _____.
A) 2 × 105
B) 8 × 10–10
C) 2 × 1020
D) 5 × 10–15.
76. The standard emf of the cell Pt|Sn2+(aq), Sn4+(aq)||Tl+(aq)|Tl is _____.
Eo
= −0.34 V
)
( Tl + / Tl
A) 0.27 V
B) 0.17 V
C) 0.47 V
D) 0.57 V
Page 14
77. The standard potential of the reaction Au+ + eฏ → Au is 1.69 V. Eฐ for
3Au+ → Au3+ + 2Au(s) is _____.
A) 3.19 V
B) 0.19 V
C) 3.57 V
D) 0.57 V
78. The metal that will not tarnish in air (with O2) is _____.
A) Cu
B) Au
C) Ag
D) Fe
79. One ampere-hour (1Aทhr) is _____.
A) 360 F
B) 3600 C
C) 36 F
D) 36,000 C
80. While discharging, the concentration of H2SO4 in a lead storage battery decreased from
38.0% by mass (d=1.29 g/mL) to 26.0% by mass (d=1.19 g/mL). It will take _____
hours to recharge the battery to the original H2SO4 concentration using a current of 22.4
A. Assume the volume of the acid remains constant at 724 mL.
A) 6.1
B) 3.6
C) 2.1
D) 1.6
81. The quantity that will not change when a cell reaction is multiplied by two is _____.
A) ∆G
B) K
C) E
D) ∆Gฐ
82. The strongest oxidizing agent below is _____.
A) F–
B) Cl2
C) F2
D) I2
Page 15
83. The pressure of H2 required to maintain equilibrium of the reaction
at 25ฐC is ____ atm. [Pb2+] = 0.035 M and the
solution is buffered at pH = 1.60.
A) 44
B) 4.4 ื 102
C) 5.1
D) 79
84. Magnesium and copper wires are immersed in 0.1 M HCl solution and joined externally
by another metal wire. Bubbles evolve at both the Mg and Cu surfaces. The following
occurs: _____
A) Hydrogen is evolved at Mg electrode.
B) Oxygen is evolved at Cu electrode.
C) Hydrogen is evolved at both electrodes.
D) Oxygen is evolved at both electrodes.
85. Eฐ for the reaction of Hg with 1 M HCl is _____.
A) 0.85 V
B) –0.45 V
C) –0.85 V
D) 0.15 V
86. _____ will oxidize Hg to Hg22+ under standard state conditions.
A) HCl
B) HNO3
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Answer Key
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D
B
C
A
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B
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C
C
B
D
B
A
A
A
D
C
B
C
C
D
C
C
A
C
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D
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B
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B
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B
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D
A
A
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A
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B
D
A
D
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B
A
A
A
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B
B
B
D
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B
C
C
B
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