Deck 20: Electrochemistry

Question 1

Table 20.2
Which of the following reactions will occur spontaneously as written?

A)3Fe²⁺ (aq) + Cr³⁺ (aq) → Cr (s) + 3Fe³⁺ (aq)
B)2Cr³⁺ (aq) + 3Sn²⁺ (aq) → 3Sn⁴⁺ (aq) + 2Cr (s)
C)Sn⁴⁺ (aq) + Fe²⁺ (s) → Sn²⁺ (aq) + Fe (s)
D)Sn²⁺ (aq) + Fe²⁺ (s) → Sn⁴⁺ (aq) + Fe³⁺ (aq)
E)2Cr (s) + 3Fe²⁺ (s) → 3Fe (s) + 2Cr³⁺ (aq)

Answer 1

2Cr (s) + 3Fe²⁺ (s) → 3Fe (s) + 2Cr³⁺ (aq)

Question 2

Table 20.1
Half Reaction E°(V)
F₂ (g) + 2e^- → 2F^- (aq)+2.87
Cl₂ (g) + 2e^- → 2Cl^- (aq)+1.359
Br₂ (l) + 2e^- → 2Br^- (aq)+1.065
O₂ (g) + 4H⁺ (aq) + 4e^- → 2H₂O (l) +1.23
Ag⁺ + e^- → Ag (s)+0.799
Fe³⁺ (aq) + e^- → Fe²⁺ (aq)+0.771
I₂ (s) + 2e^- → 2I^- (aq)+0.536
Cu²⁺ + 2e^- → Cu (s)+0.34
2H⁺ + 2e^- → H₂ (g) 0
Pb²⁺ + 2e^- → Pb (s)-0.126
Ni²⁺ + 2e^- → Ni (s)-0.28
Li⁺ + e^- → Li (s)-3.05
Which one of the following is the best oxidizing agent?

A)H₂
B)Na
C)O₂
D)Li
E)Ca

Answer 2

O₂

Question 3

Which element is reduced in the reaction below? Fe²⁺ + H⁺ + Cr₂O₇^2- → Fe³⁺ + Cr³⁺ + H₂O

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

Answer 3

Cr

Question 4

Which transformation could take place at the anode of an electrochemical cell?

A)NO → NO₃^-
B)CO₂ → C₂O₄^2-
C)VO₂⁺ → VO²⁺
D)H₂AsO₄ → H₃AsO₃
E)O₂ → H₂O₂

Question 5

Which element is reduced in the reaction below? Fe(CO)₅ (l) + 2HI (g) → Fe(CO)₄I₂ (s) + CO (g) + H₂ (g)

A)Fe
B)C
C)O
D)H
E)I

Question 6

Which substance is the oxidizing agent in the following reaction? Fe₂S₃ + 12HNO₃ → 2Fe(NO₃)₃ + 3S + 6NO₂ + 6H₂O

A)HNO₃
B)S
C)NO₂
D)Fe₂S₃
E)H₂O

Question 7

The purpose of the salt bridge in an electrochemical cell is to ________.

A)maintain electrical neutrality in the half-cells via migration of ions
B)provide a source of ions to react at the anode and cathode
C)provide oxygen to facilitate oxidation at the anode
D)provide a means for electrons to travel from the anode to the cathode
E)provide a means for electrons to travel from the cathode to the anode

Question 8

Which transformation could take place at the anode of an electrochemical cell?

A)Cr₂O₇^2- → Cr²⁺
B)F₂ to F^-
C)O₂ to H₂O
D)HAsO₂ to As
E)None of the above could take place at the anode.

Question 9

Which one of the following reactions is a redox reaction?

A)NaOH + HCl → NaCl + H₂O
B)Pb²⁺ + 2Cl^- → PbCl₂
C)AgNO₃ + HCl → HNO₃ + AgCl
D)None of the above is a redox reaction.

Question 10

Table 20.1
Half Reaction E°(V)
F₂ (g) + 2e^- → 2F^- (aq)+2.87
Cl₂ (g) + 2e^- → 2Cl^- (aq)+1.359
Br₂ (l) + 2e^- → 2Br^- (aq)+1.065
O₂ (g) + 4H⁺ (aq) + 4e^- → 2H₂O (l) +1.23
Ag⁺ + e^- → Ag (s)+0.799
Fe³⁺ (aq) + e^- → Fe²⁺ (aq)+0.771
I₂ (s) + 2e^- → 2I^- (aq)+0.536
Cu²⁺ + 2e^- → Cu (s)+0.34
2H⁺ + 2e^- → H₂ (g) 0
Pb²⁺ + 2e^- → Pb (s)-0.126
Ni²⁺ + 2e^- → Ni (s)-0.28
Li⁺ + e^- → Li (s)-3.05
Which one of the following types of elements is most likely to be a good oxidizing agent?

A)alkali metals
B)lanthanides
C)alkaline earth elements
D)transition elements
E)halogens

Question 11

Consider an electrochemical cell based on the reaction: 2H⁺ (aq) + Sn (s) → Sn²⁺ (aq) + H₂ (g)
Which of the following actions would change the measured cell potential?

A)increasing the pH in the cathode compartment
B)lowering the pH in the cathode compartment
C)increasing the [Sn²⁺] in the anode compartment
D)increasing the pressure of hydrogen gas in the cathode compartment
E)Any of the above will change the measure cell potential.

Question 12

What is the coefficient of the permanganate ion when the following equation is balanced? MnO₄^- + Br^- → Mn²⁺ + Br₂ (acidic solution)

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

Question 13

Which of the following reactions is a redox reaction? (a) K₂CrO₄ + BaCl₂ → BaCrO₄ + 2KCl
(b) Pb₂²⁺ + 2Br^- → PbBr
(c) Cu + S → CuS

A)(a)only
B)(b)only
C)(c)only
D)(a)and (c)
E)(b)and (c)

Question 14

Which transformation could take place at the cathode of an electrochemical cell?

A)MnO₂ → MnO₄^-
B)Br₂ → BrO₃^-
C)NO → HNO₂
D)HSO₄^- → H₂SO₃
E)Mn²⁺ → MnO₄^-

Question 15

Table 20.1
Half Reaction E°(V)
F₂ (g) + 2e^- → 2F^- (aq)+2.87
Cl₂ (g) + 2e^- → 2Cl^- (aq)+1.359
Br₂ (l) + 2e^- → 2Br^- (aq)+1.065
O₂ (g) + 4H⁺ (aq) + 4e^- → 2H₂O (l) +1.23
Ag⁺ + e^- → Ag (s)+0.799
Fe³⁺ (aq) + e^- → Fe²⁺ (aq)+0.771
I₂ (s) + 2e^- → 2I^- (aq)+0.536
Cu²⁺ + 2e^- → Cu (s)+0.34
2H⁺ + 2e^- → H₂ (g) 0
Pb²⁺ + 2e^- → Pb (s)-0.126
Ni²⁺ + 2e^- → Ni (s)-0.28
Li⁺ + e^- → Li (s)-3.05
Which of the halogens in Table 20.1 is the strongest oxidizing agent?

A)Cl₂
B)Br₂
C)F₂
D)I₂
E)All of the halogens have equal strength as oxidizing agents.

Question 16

Consider an electrochemical cell based on the reaction: 2H⁺ (aq) + Sn (s) → Sn²⁺ (aq) + H₂ (g)
Which of the following actions would not change the measured cell potential?

A)lowering the pH in the cathode compartment
B)addition of more tin metal to the anode compartment
C)increasing the tin (II)ion concentration in the anode compartment
D)increasing the pressure of hydrogen gas in the cathode compartment
E)Any of the above will change the measured cell potential.

Question 17

What is the coefficient of Fe³⁺ when the following equation is balanced? CN^- + Fe³⁺ → CNO^- + Fe²⁺ (basic solution)

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

Question 18

Table 20.2
Which of the following reactions will occur spontaneously as written?

A)Sn⁴⁺ (aq) + Fe³⁺ (aq) → Sn²⁺ (aq) + Fe²⁺ (aq)
B)3Fe (s) + 2Cr³⁺ (aq) → 2Cr (s) + 3Fe²⁺ (aq)
C)Sn⁴⁺ (aq) + Fe²⁺ (aq) → Sn²⁺ (aq) + Fe (s)
D)3Sn⁴⁺ (aq) + 2Cr (s) → 2Cr³⁺ (aq) + 3Sn²⁺ (aq)
E)3Fe²⁺ (aq) → Fe (s) + 2Fe³⁺ (aq)

Question 19

What is the coefficient of the dichromate ion when the following equation is balanced? Fe²⁺ + Cr₂O₇^2- → Fe³⁺ + Cr³⁺ (acidic solution)

A)1
B)2
C)3
D)5
E)6

Question 20

Which element is reduced in the reaction below? I^- + MnO₄^- + H⁺ → I₂ + MnO₂ + H₂O

A)I
B)Mn
C)O
D)H

Question 21

What is the oxidation number of oxygen in H₂O₂?

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

Question 22

What is the oxidation number of manganese in MnO₂?

A)+3
B)+2
C)+1
D)+4
E)+7

Question 23

________ is the oxidizing agent in the reaction below. Cr₂O₇^2- + 6S₂O₃^2- + 14H⁺ → 2Cr³⁺ + 3S₄O₆^2- + 7H₂O

A)Cr₂O₇^2-
B)S₂O₃^2-
C)H⁺
D)Cr³⁺
E)S₄O₆^2-

Question 24

The gain of electrons by an element is called ________.

A)reduction
B)oxidation
C)disproportionation
D)fractionation
E)sublimation

Question 25

Cathodic protection of a metal pipe against corrosion usually entails ________.

A)attaching an active metal to make the pipe the anode in an electrochemical cell
B)coating the pipe with another metal whose standard reduction potential is less negative than that of the pipe
C)attaching an active metal to make the pipe the cathode in an electrochemical cell
D)attaching a dry cell to reduce any metal ions which might be formed
E)coating the pipe with a fluoropolymer to act as a source of fluoride ion (since the latter is so hard to oxidize)

Question 26

Which substance is the reducing agent in the reaction below? Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O

A)Pb
B)H₂SO₄
C)PbO₂
D)PbSO₄
E)H₂O

Question 27

Which substance is serving as the reducing agent in the following reaction? 14H⁺ + Cr₂O₇^2- + 3Ni → 3Ni²⁺ + 2Cr³⁺ + 7H₂O

A)Ni
B)H⁺
C)Cr₂O₇^2-
D)H₂O
E)Ni²⁺

Question 28

What is the oxidation number of potassium in KMnO₄?

A)0
B)+1
C)+2
D)-1
E)+3

Question 29

________ is reduced in the following reaction: Cr₂O₇^2- + 6S₂O₃^2- + 14H⁺ → 2Cr³⁺ + 3S₄O₆² + 7H₂O

A)Cr⁶⁺
B)S²⁺
C)H⁺
D)O^2-
E)S₄O₆^2-

Question 30

________ is the reducing agent in the reaction below. Cr₂O₇^2- + 6S₂O₃^2- + 14H⁺ → 2Cr³⁺ + 3S₄O₆^2- + 7H₂O

A)Cr₂O₇^2-
B)S₂O₃^2-
C)H⁺
D)Cr³⁺
E)S₄O₆^2-

Question 31

What is the cathode in the hydrogen fuel cell?

A)O₂
B)KOH
C)Li
D)H₂
E)Pt

Question 32

What is the cathode in an alkaline battery?

A)MnO₂
B)KOH
C)Zn powder
D)Mn₂O₃
E)Pt

Question 33

Which substance is serving as the oxidizing agent in the following reaction? 14H⁺ + Cr₂O₇^2- + 3Ni → 3Ni²⁺ + 2Cr³⁺ + 7H₂O

A)Ni
B)H⁺
C)Cr₂O₇^2-
D)H₂O
E)Ni²⁺

Question 34

What is the oxidation number of manganese in the MnO₄^1- ion?

A)+1
B)+2
C)+5
D)+4
E)+7

Question 35

Which substance is the oxidizing agent in the reaction below? Pb + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O

A)Pb
B)H₂SO₄
C)PbO₂
D)PbSO₄
E)H₂O

Question 36

What is the anode in an alkaline battery?

A)MnO₂
B)KOH
C)Zn powder
D)Mn₂O₃
E)Pt

Question 37

In a lead-acid battery, the electrodes are consumed. In this battery, ________.

A)the anode is Pb
B)the anode is PbSO₄
C)the anode is PbO₂
D)the cathode is PbSO₄
E)the cathode is Pb

Question 38

One of the differences between a voltaic cell and an electrolytic cell is that in an electrolytic cell, ________.

A)an electric current is produced by a chemical reaction
B)electrons flow toward the anode
C)a nonspontaneous reaction is forced to occur
D)O₂ gas is produced at the cathode
E)oxidation occurs at the cathode

Question 39

________ is oxidized in the following reaction: Cr₂O₇^2- + 6S₂O₃^2- + 14H⁺ → 2Cr³⁺ + 3S₄O₆^2- + 7H₂O

A)Cr⁶⁺
B)S²⁺
C)H⁺
D)O^2-
E)S₄O₆^2-

Question 40

What is the oxidation number of chromium in Cr₂O₇^2- ion?

A)+3
B)+12
C)+7
D)+6
E)+14

Question 41

In a voltaic cell, electrons flow from the ________ to the ________.

A)salt bride, anode
B)anode, salt bridge
C)cathode, anode
D)salt bridge, cathode
E)anode, cathode

Question 42

1V = ________.

A)1 amp ∙ s
B)1 J/s
C)96485 C
D)1 J/C
E)1 C/J

Question 43

The electrode at which oxidation occurs is called the ________.

A)oxidizing agent
B)cathode
C)reducing agent
D)anode
E)voltaic cell

Question 44

Table 20.2
The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is ________ V. Cr (s) + 3Fe³⁺ (aq) → 3Fe²⁺ (aq) + Cr³⁺ (aq)

A)-1.45
B)+2.99
C)+1.51
D)+3.05
E)+1.57

Question 45

Table 20.2
The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is ________ V. 2Cr (s) + 3Fe²⁺ (aq) → 3Fe (s) + 2Cr³⁺ (aq)

A)+0.30
B)+2.80
C)+3.10
D)+0.83
E)-0.16

Question 46

The balanced half-reaction in which sulfate ion is reduced to sulfite ion is a ________ process.

A)four-electron
B)one-electron
C)two-electron
D)three-electron
E)six-electron

Question 47

The half-reaction occurring at the anode in the balanced reaction shown below is ________. 3MnO₄^- (aq) + 24H⁺ (aq) + 5Fe (s) → 3Mn²⁺ (aq) + 5Fe³⁺ (aq) + 12H₂O (l)

A)MnO₄^- (aq) + 8H⁺ (aq) + 5e^- → Mn²⁺ (aq) + 4H₂O (l)
B)2MnO₄^- (aq) + 12H⁺ (aq) + 6e^- → 2Mn²⁺ (aq) + 3H₂O (l)
C)Fe (s) → Fe³⁺ (aq) + 3e^-
D)Fe (s) → Fe²⁺ (aq) + 2e^-
E)Fe²⁺ (aq) → Fe³⁺ (aq) + e^-

Question 48

The relationship between the change in Gibbs free energy and the emf of an electrochemical cell is given by ________.

A)ΔG =
B)ΔG =
C)ΔG = -nFE
D)ΔG = -nRTF
E)ΔG =

Question 49

Table 20.2
The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is ________ V. 3Sn⁴⁺ (aq) + 2Cr (s) → 2Cr³⁺ (aq) + 3Sn²⁺ (aq)

A)+1.94
B)+0.89
C)+2.53
D)-0.59
E)-1.02

Question 50

The standard cell potential (E°_cell)of the reaction below is -0.34 V. The value of ΔG° for the reaction is ________ kJ/mol. Cu (s) + 2H⁺ (aq) → Cu²⁺ (aq) + H₂ (g)

A)-0.34
B)+66
C)-130
D)+130
E)none of the above

Question 51

The more ________ the value of E°_red, the greater the driving force for reduction.

A)positive
B)negative
C)exothermic
D)endothermic
E)extensive

Question 52

Table 20.2
The standard cell potential (E°_cell)for the voltaic cell based on the reaction below is ________ V. Sn²⁺ (aq) + 2Fe³⁺ (aq) → 2Fe²⁺ (aq) + Sn⁴⁺ (aq)

A)+0.46
B)+0.617
C)+1.39
D)-0.46
E)+1.21

Question 53

The standard cell potential (E°_cell)of the reaction below is -0.55 V. The value of ΔG° for the reaction is ________ J/mol. I₂ (s) + 2Br^- (aq) → 2I^- (aq) + Br₂ (l)

A)0.54
B)0.55
C)5.5 × 10^-6
D)1.1 × 10⁵
E)none of the above

Question 54

The reduction half reaction occurring in the standard hydrogen electrode is ________.

A)H₂ (g, 1 atm) → 2H⁺ (aq, 1M) + 2e^-
B)2H⁺ (aq) + 2OH^- → H₂O (l)
C)O₂ (g) + 4H⁺ (aq)+ 4e^- → 2H₂O (l)
D)2H⁺ (aq, 1M) + 2e^- → H₂ (g, 1 atm)
E)2H⁺ (aq, 1M) + Cl₂ (aq) → 2HCl (aq)

Question 55

________ electrons appear in the following half-reaction when it is balanced. S₄O₆^2- → 2S₂O₃^2-

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

Question 56

The standard cell potential (E°_cell)of the reaction below is +0.126 V. The value of ΔG° for the reaction is ________ kJ/mol. Pb (s) + 2H⁺(aq) → Pb²⁺ (aq) + H₂ (g)

A)-24.3
B)+24.3
C)-12.6
D)+12.6
E)-50.8

Question 57

The balanced half-reaction in which chlorine gas is reduced to the aqueous chloride ion is a ________ process.

A)one-electron
B)two-electron
C)four-electron
D)three-electron
E)six-electron

Question 58

The half-reaction occurring at the cathode in the balanced reaction shown below is ________. 3MnO₄^- (aq) + 24H⁺ (aq) + 5Fe (s) → 3Mn²⁺ (aq) + 5Fe³⁺ (aq) + 12H₂O (l)

A)MnO₄^- (aq) + 8H⁺ (aq) + 5 → Mn²⁺ (aq) + 4H₂O (l)
B)2MnO₄^- (aq) + 12H⁺ (aq) + 6e^- → 2Mn²⁺ (aq) + 3H₂O (l)
C)Fe (s) → Fe³⁺ (aq) + 3e^-
D)Fe (s) → Fe²⁺ (aq) + 2e^-
E)Fe²⁺ (aq) → Fe³⁺ (aq) + e^-

Question 59

The balanced half-reaction in which dichromate ion is reduced to chromium (III)ion is a ________ process.

A)four-electron
B)twelve-electron
C)three-electron
D)six-electron
E)two-electron

Question 60

The balanced half-reaction in which dichromate ion is reduced to chromium metal is a ________ process.

A)two-electron
B)six-electron
C)three-electron
D)four-electron
E)twelve-electron

Question 61

What is the oxidation number of phosphorous in the PH₃ molecule?

A)-3
B)-4
C)-5
D)+1
E)0

Question 62

Which element is oxidized in the reaction below? I^- + MnO₄^- + H⁺ → I₂ + MnO₂ + cO

A)I
B)Mn
C)O
D)H

Question 63

Which substance is the oxidizing agent in the reaction below? Fe(CO)₅ (l) + 2HI (g) → Fe(CO)₄I₂ (s) + CO (g) + H₂ (g)

A)HI
B)Fe(CO)₅
C)Fe(CO)₄I₂
D)CO
E)H₂

Question 64

The standard cell potential (E° cell)for the reaction below is +0.63 V. The cell potential for this reaction is ________ V when [ Zn²⁺] = 3.0 M and [Pb²⁺] = 2.0 × 10^-4 M. Pb²⁺ (aq) + Zn (s) → Zn²⁺ (aq) + Pb (s)

A)0.51
B)0.86
C)0.40
D)0.75
E)0.63

Question 65

What is the oxidation number of sulfur in the S₂O₃^2- ion?

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

Question 66

In the galvanic cell using the redox reaction below, the reduction half-reaction is ________. Zn (s) + Cu²⁺ (aq) → Zn²⁺ (aq) + Cu (s)

A)Cu²⁺ + 2e^- → Cu
B)Zn → Zn²⁺ + 2e^-
C)Cu²⁺ → Cu + 2e^-
D)Zn + 2e^- → Zn²⁺

Question 67

What is the correct coefficient for the electrons in the following half-reaction: Ni⁶⁺ + ___e^- → Ni

A)6
B)1
C)2
D)3
E)5

Question 68

What is the oxidation number of bromine in the HBrO molecule?

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

Question 69

Which element is reduced in the following reaction? Fe₂S₃ + 12HNO₃ → 2Fe(NO₃)₃ + 3S + 6NO₂ + 6H₂O

A)N
B)S
C)H
D)O
E)NO₂

Question 70

What is the oxidation number of nitrogen in the NH₂OH molecule?

A)-1
B)-2
C)-3
D)0
E)+1

Question 71

A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is AgCl (s) + e^- → Ag (s) + Cl^- (aq)E° = +0.222 V
The concentrations of chloride ion in the two compartments are 0.0100 M and 1.55 M, respectively. The cell emf is ________ V.

A)0.216
B)0.130
C)0.00143
D)34.4
E)0.228

Question 72

In the electrochemical cell using the redox reaction below, the oxidation half reaction is ________. Sn⁴⁺ (aq) + Fe (s)→ Sn²⁺ (aq) + Fe²⁺ (aq)

A)Sn⁴⁺ + 2e^- → Sn²⁺
B)Fe → Fe²⁺ + 2e^-
C)Sn⁴⁺ → Sn²⁺ + 2e^-
D)Fe + 2e^- → Fe²⁺
E)Fe + 2e^- → Sn²⁺

Question 73

In the electrochemical cell using the redox reaction below, the cathode half-reaction is ________. 2H⁺ (s) + Sn (s) → Sn²⁺ (aq) + H₂ (g)

A)2H⁺ + 2e^- → H₂
B)Sn → Sn²⁺ + 2e^-
C)2H⁺ → H₂ + 2e^-
D)Sn + 2e^- → Sn²⁺
E)Sn + 2e^- → H₂

Question 74

Galvanized iron is iron coated with ________.

A)magnesium
B)zinc
C)chromium
D)phosphate
E)iron oxide

Question 75

Which element is reduced in the reaction below? Fe²⁺ + H⁺ + Cr₂O₇^2- → Fe³⁺ + Cr³⁺ + H₂O

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

Question 76

The standard cell potential (E° cell)for the reaction below is +1.10 V. The cell potential for this reaction is ________ V when the concentration of [Cu²⁺] = 1.0 × 10^-5 M and [Zn²⁺] = 3.0 M. Zn (s) + Cu²⁺ (aq) → Cu (s) + Zn²⁺ (aq)

A)1.42
B)1.26
C)0.94
D)0.78
E)1.10

Question 77

The standard cell potential (E°_cell)of the reaction below is +1.34 V. The value of ΔG° for the reaction is ________ kJ/mol. 3 Cu (s) + 2 MnO₄^- (aq)+ 8H⁺ (aq) → 3 Cu²⁺ (aq)+ 2 MnO₂ (s) + 4 H₂O (l)

A)-24.3
B)+259
C)-259
D)+776
E)-776

Question 78

The lead-containing reactant(s)consumed during recharging of a lead-acid battery is/are ________.

A)Pb (s)only
B)PbO₂ (s)only
C)PbSO₄ (s)only
D)both PbO₂ (s)and PbSO₄ (s)
E)both Pb (s)and PbO₂ (s)

Question 79

The standard cell potential (E°)of a voltaic cell constructed using the cell reaction below is 0.76 V: Zn (s) + 2H⁺ (aq) → Zn²⁺ (aq) + H₂ (g)
With P_H2 = 1.0 atm and [Zn²⁺] = 1.0 M, the cell potential is 0.53 V. The concentration of H⁺ in the cathode compartment is ________ M.

A)1.3 × 10^-4
B)1.7 × 10^-8
C)1.1 × 10^-2
D)7.7 × 10³
E)1.3 × 10^-11

Question 80

Corrosion of iron is retarded by ________.

A)the presence of salts
B)high pH conditions
C)low pH conditions
D)both the presence of salts and high pH conditions
E)both the presence of salts and low pH conditions