Deck 18: Electrochemistry

Question 1

Determine the cell diagram for the reaction below. Assume platinum electrodes are used when no other solid is present.
Cl₂(g) + Sn²⁺(aq) $\rarr$ Sn⁴⁺(aq) + 2Cl^-(aq)

A) Pt(s) | Cl₂(g) | Cl^-(aq) || Sn²⁺(aq), Sn⁴⁺(aq) | Pt(s)
B) Pt(s) | Sn²⁺(aq), Sn⁴⁺(aq) || Cl₂(g) | Cl^-(aq) | Pt(s)
C) Pt(s) | Sn⁴⁺(aq), Sn²⁺(aq) || Cl^-(aq) | Cl₂(g) | Pt(s)
D) Pt(s) | Cl^-(g) | Cl₂(aq) || Sn⁴⁺(aq), Sn²⁺(aq) | Pt(s)
E) Pt(s) | Cl₂(g) | Sn²⁺(aq) || Sn⁴⁺(aq), Cl^-(aq) | Pt(s)

Answer 1

Pt(s) | Sn²⁺(aq), Sn⁴⁺(aq) || Cl₂(g) | Cl^-(aq) | Pt(s)

Question 2

A balanced redox equation must have which of the following:
I. The same number of each type of atom on both sides of the equation
II. The total number electrons lost in the oxidation equal to total number of electrons gained in the reduction
III. The same total charge of all ionic species on both sides of the reaction
IV. H₂O present as a product or a reactant

A) I, II, and III
B) I and II
C) I, III, and IV
D) I, II, III, and IV
E) III and IV

Answer 2

I, II, and III

Question 3

Complete and balance the following redox equation. The sum of the smallest whole-number coefficients is Bi(OH)₃ + SnO₂^2- $\rarr$ Bi + SnO₃^2- (basic solution)

A) 32.
B) 25.
C) 16.
D) 13.
E) None of these.

Answer 3

13.

Question 4

Complete and balance the following redox equation. When properly balanced using the smallest whole-number coefficients, the coefficient of S is H₂S + HNO₃ $\rarr$ S + NO (acidic solution)

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

Question 5

Consider a Galvanic cell constructed from the following half cells, linked by an external circuit and by a KCl salt bridge.- an Al(s) electrode in 1.0 M Al(NO₃)₃ solution - a Pb(s) electrode in 1.0 M Pb(NO₃)₂ solution
The balanced overall (net) cell reaction is

A)Pb(s) + Al³⁺(aq) $\rarr$ Pb²⁺(aq) + Al(s.)
B)3Pb(s) + 2Al³⁺(aq) $\rarr$ 3Pb²⁺(aq) + 2Al(s).
C)3Pb²⁺(aq) + 2Al(s) $\rarr$ 3Pb(s) + 2Al³⁺(aq).
D)Pb²⁺(aq) + Al(s) $\rarr$ Pb(s) + Al³⁺(aq).

Question 6

Given the following notation for an electrochemical cell
Pt(s) | H₂(g) | H⁺(aq) || Ag⁺(aq) | Ag(s)
What is the balanced overall (net) cell reaction

A)2H⁺(aq) + 2Ag⁺(aq) $\rarr$ H₂(g) + 2Ag(s)
B)H₂(g) + 2Ag(s) $\rarr$ H⁺(aq) + 2Ag⁺(aq)
C)2H⁺(aq) + 2Ag(s) $\rarr$ H₂(g) + 2Ag⁺(aq)
D)H₂(g) + Ag⁺(aq) $\rarr$ H⁺(aq) + Ag(s)
E)H₂(g) + 2Ag⁺(aq) $\rarr$ 2H⁺(aq) + 2Ag(s)

Question 7

Complete and balance the following redox equation that occurs in acidic solution using the set of smallest whole-number coefficients. What is the sum of all the coefficients in the equation
PbO₂(s) + Cl^- $\rarr$ Pb²⁺ + Cl₂(g) (acidic solution)

A) 2
B) 4
C) 5
D) 9
E) 11

Question 8

Complete and balance the following redox equation. What is the coefficient of H₂O when the equation is balanced using the set of smallest whole-number coefficients
MnO₄^- + SO₃^2- $\rarr$ Mn²⁺ + SO₄^2- (acidic solution)

A) 3
B) 4
C) 5
D) 8
E) None of these.

Question 9

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the overall redox equation: Cr₂O₇^2-(aq) + 6Fe²⁺(aq) + 14H⁺(aq) $\rarr$ 2Cr³⁺(aq) + 6Fe³⁺(aq) + 7H₂O(l)

A) 1
B) 2
C) 3
D) 6
E) 12

Question 10

Given the following cell diagram, Al(s) | Al³⁺(aq) || Cd²⁺(aq) | Cd (s)
What is the balanced overall (net) cell reaction

A)Al(s) + Cd²⁺(aq) $\rarr$ Al³⁺(aq) + Cd (s)
B)Al³⁺(aq) + Cd (s) $\rarr$ Al(s) + Cd²⁺(aq)
C)2Al(s) + 3Cd²⁺(aq) $\rarr$ 2Al³⁺(aq) + 3Cd (s)
D)2Al³⁺(aq) + 3Cd (s) $\rarr$ 2Al(s) + 3Cd²⁺(aq)
E)3Al³⁺(aq) + 2Cd (s) $\rarr$ 3Al(s) + 2Cd²⁺(aq)

Question 11

Complete and balance the following redox equation. The sum of the smallest whole-number coefficients is MnO₄^- + H⁺ + Br^- $\rarr$ Mn²⁺ + Br₂ + H₂O (acidic solution)

A) 6.
B) 17.
C) 21.
D) 29.
E) 43.

Question 12

Complete and balance the following redox equation. What is the coefficient of H₂O when the equation is balanced with the set of smallest whole-number coefficients
H₂O + MnO₄^- + I^- $\rarr$ MnO₂ + IO₃^- (basic solution)

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

Question 13

Complete and balance the following redox equation using the set of smallest whole-number coefficients. What is the sum of the coefficients
HI + HNO₃ $\rarr$ I₂ + NO (acidic solution)

A) 5
B) 7
C) 14
D) 17
E) None of these.

Question 14

What is the total number of moles (n) of electrons exchanged between the oxidizing agent and the reducing agent in the overall redox equation: 5 Ag⁺(aq) + Mn²⁺(aq) + 4H₂O(l) $\rarr$ 5Ag(s) + MnO₄^-(aq) + 8H⁺(aq)

A) 1
B) 2
C) 3
D) 5
E) 7

Question 15

Determine the cell diagram for the reaction below. Assume a platinum electrode is used when no other solid is present.
2Fe²⁺(aq) + Pb²⁺(aq) $\rarr$ 2Fe³⁺(aq) + Pb(s)

A) Pt(s) | Fe²⁺(aq), Fe³⁺(aq) || Pb²⁺(aq) | Pb(s)
B) Pb(s) | Pb²⁺(aq) || Fe²⁺(aq), Fe³⁺(aq) | Pt(s)
C) Pt(s) | Fe³⁺(aq), Fe²⁺(aq) || Pb(s) | Pb²⁺(aq) | Pt(s)
D) Pt(s) | Pb²⁺(aq) | Pb(s) || Fe²⁺(aq), Fe³⁺(aq) | Pt(s)
E) Pt(s) | Fe²⁺(aq), Pb²⁺(aq) || Fe³⁺(aq) | Pb(s)

Question 16

Complete and balance the following redox equation. The sum of the smallest whole-number coefficients is Br₂ $\rarr$ BrO₃^- + Br^- (basic solution)

A) 9.
B) 12.
C) 18.
D) 21.
E) None of the above.

Question 17

Complete and balance the following redox equation using the set of smallest whole-number coefficients. Now sum the coefficients of all species in the balanced equation. (Remember the coefficients that are equal to one.) The sum of the coefficients is BrO₃^-(aq) + Sb³⁺(aq) $\rarr$ Br^-(aq) + Sb⁵⁺(aq) (acidic solution)

A) 4.
B) 12.
C) 13.
D) 17.
E) None of these.

Question 18

Complete and balance the following redox equation. What is the coefficient of H₂S when the equation is balanced using the set of smallest whole-number coefficients
H₂S + MnO₄^- $\rarr$ Mn²⁺ + SO₄^2- (acidic solution)

A) 1
B) 2
C) 4
D) 5
E) None of these.

Question 19

Complete and balance the following redox equation. What is the coefficient of OH^- when the equation is balanced using the set of smallest whole-number coefficients
MnO₄^- + I^- $\rarr$ MnO₂ + IO₃^- (basic solution)

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

Question 20

Complete and balance the following redox equation using the smallest whole-number coefficients. What is the coefficient of Sn in the balanced equation?
Sn + HNO₃ $\rarr$ SnO₂ + NO₂ + H₂O (acidic solution)

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

Question 21

Consider a voltaic cell based on the following cell reaction: Ni(s) + At₂(s) $\rarr$ Ni²⁺(aq) + 2At^- (aq)
Given that the standard cell emf is 0.55 V, what is the standard reduction potential for astatine
[E ^$\circ$ (Ni²⁺/Ni) = -0.25 V]

A) 0.80 V
B) 0.30 V
C) -0.30 V
D) -0.80 V
E) 0.43 V

Question 22

Calculate E ^$\circ$ _cell for a silver-aluminum cell in which the cell reaction is
Al(s) + 3Ag⁺(aq) $\rarr$ Al³⁺(aq) + 3Ag(s).

A) -2.46 V
B) 0.86 V
C) -0.86 V
D) 2.46 V
E) none of these

Question 23

Consider an electrochemical cell constructed from the following half cells, linked by a KCl salt bridge.
- a Fe electrode in 1.0 M FeCl₂ solution
- a Sn electrode in 1.0 M Sn(NO₃)₂ solution
When the cell is running spontaneously, which choice includes only true statements and no false ones

A) The tin electrode loses mass and the tin electrode is the cathode.
B) The tin electrode gains mass and the tin electrode is the cathode.
C) The iron electrode gains mass and the iron electrode is the anode.
D) The iron electrode loses mass and the iron electrode is the cathode.
E) The iron electrode gains mass and the iron electrode is the cathode.

Question 24

Calculate the standard cell emf for the following cell: Mg | Mg²⁺ || NO₃^- (acid soln)| NO(g) | Pt

A) 3.33 V
B) 1.41 V
C) -1.41 V
D) 8.46 V
E) -8.46 V

Question 25

A galvanic cell has the overall reaction: 2Fe(NO₃)₂(aq) + Pb(NO₃)₂(aq) $\rarr$ 2Fe(NO₃)₃(aq) + Pb(s)
Which is the half reaction occurring at the cathode

A)NO₃^-(aq) + 4H⁺(aq) + 3e^- $\rarr$ NO(g) + 2H₂O(l)
B)NO₃^-(aq) + 2H⁺(aq) + e^- $\rarr$ NO₂(g) + H₂O(l)
C)Fe²⁺(aq) $\rarr$ Fe³⁺(aq) + e^-
D)Pb²⁺(aq) + 2e^- $\rarr$ Pb(s)
E)Fe²⁺(aq) + e^- $\rarr$ Fe³⁺(aq)

Question 26

Which one of the following reactions will occur spontaneously at standard-state conditions and 25 ^$\circ$ C

A)Mg²⁺ + Ca $\rarr$ Mg + Ca²⁺
B)Au + 3K⁺ $\rarr$ Au³⁺ + 3K
C)2Al³⁺ + 3Fe $\rarr$ 2Al + 3Fe²⁺
D)Cu + 2H⁺ $\rarr$ Cu²⁺ + H₂
E)Ni²⁺ + 2Fe²⁺(aq) $\rarr$ Ni(s) + 2Fe³⁺(aq)

Question 27

Which one of the following reactions will occur spontaneously at standard-state conditions and 25 ^$\circ$ C

A)Br₂(l) + Sn(s) $\rarr$ 2Br^-(aq) + Sn²⁺(aq)
B)Fe²⁺(aq) + Ni(s) $\rarr$ Fe(s) + Ni²⁺(aq)
C)2Ag⁺(aq) 2H₂O(l) $\rarr$ 2Ag(s) + 2H⁺(aq) + H₂O₂(aq)
D)Mn²⁺(aq) + Cd(s) $\rarr$ Mn(s) + Cd²⁺(aq)
E)Cr³⁺(aq) + 3Cu⁺(aq) $\rarr$ Cr(s) + 3Cu²⁺(aq)

Question 28

Which of the following is true concerning a galvanic cell

A) Oxidation occurs at the anode and is where anions move towards
B) Oxidation occurs at the cathode and is where anions move towards
C) Oxidation occurs at the anode and is where cations move towards
D) Oxidation occurs at the cathode and is where cations move towards
E) Reduction occurs at the anode and is where anions move towards

Question 29

For the reaction, 2Cr²⁺ + Cl₂(g) $\rarr$ 2Cr³⁺ + 2Cl^-, E ^$\circ$ _cell is 1.78 V. Calculate E ^$\circ$ _cell for the related reaction Cr³⁺ + Cl^- $\rarr$ Cr²⁺ + ¹/₂Cl₂(g).

A) 1.78 V
B) 0.89 V
C) -1.78 V
D) -0.89 V
E) None of these.

Question 30

An electrochemical cell based on the following reaction has a standard cell voltage (E ^$\circ$ _cell) of 0.48 V: Sn(s) + Cu²⁺(aq) $\rarr$ Sn²⁺(aq) + Cu(s)
What is the standard reduction potential of tin(II)
(E ^$\circ$ (Cu²⁺/Cu) = 0.34 V)

A) -0.14 V
B) 0.14 V
C) -0.82 V
D) 0.82 V
E) none of these

Question 31

The overall reaction 2Co³⁺(aq) + 2Cl^-(aq) $\rarr$ 2Co²⁺(aq) + Cl₂(g) has the standard cell voltage E ^$\circ$ _cell= 0.46 V. Given E ^$\circ$ = 1.36 V for the reaction Cl₂(g) + 2e^- $\rarr$ 2Cl^-(aq), calculate the standard reduction potential for the following the half reaction at 25 ^$\circ$ C: Co³⁺ + e^- $\rarr$ Co²⁺

A) 1.82 V
B) -0.90 V
C) 0.90 V
D) -1.82 V
E) -1.36 V

Question 32

Calculate E ^$\circ$ _cell for the following reaction: 2Fe²⁺(aq) + Cd²⁺(aq) $\rarr$ 2Fe³⁺(aq) + Cd(s)

A) -0.37 V
B) 0.37 V
C) -1.17 V
D) 1.17 V
E) None of these.

Question 33

For the reaction Ni²⁺(aq) + 2Fe²⁺(aq) $\rarr$ Ni(s) + 2Fe³⁺(aq), the standard cell potential E ^$\circ$ _cell is

A) +2.81 V.
B) +1.02 V.
C) +0.52 V.
D) -1.02 V.
E) -2.81 V.

Question 34

Consider an electrochemical cell based on the following cell diagram:
Pt | Pu³⁺(aq), Pu⁴⁺(aq) || Cl₂(g), Cl^- (aq) | Pt
Given that the standard cell emf is 0.35 V and that the standard reduction potential of chlorine is 1.36 V, what is the standard reduction potential E ^$\circ$ (Pu⁴⁺/Pu³⁺)

A) 2.37 V
B) 1.01 V
C) -1.71 V
D) -1.01 V
E) 1.71 V

Question 35

Consider an electrochemical cell constructed from the following half cells, linked by a KCl salt bridge.
- a Fe electrode in 1.0 M FeCl₂ solution
- a Ni electrode in 1.0 M Ni(NO₃)₂ solution
When the cell is running spontaneously, which choice includes only true statements and no false ones

A) The nickel electrode loses mass and the nickel electrode is the cathode.
B) The nickel electrode gains mass and the nickel electrode is the cathode.
C) The iron electrode gains mass and the iron electrode is the anode.
D) The iron electrode loses mass and the iron electrode is the cathode.

Question 36

Consider the following electrochemical cell: U | U³⁺(aq) || Cl^-(aq),Cl₂(g) | Pt
If the standard cell emf is 3.16 V, what is the standard reduction potential for uranium

A) -3.16 V
B) +3.16 V
C) -1.80 V
D) +1.80 V
E) +1.36 V

Question 37

Which of the following is true concerning a galvanic cell

A) Reduction occurs at the anode and is where anions move towards
B) Reduction occurs at the cathode and is where anions move towards
C) Reduction occurs at the cathode and is where cations move towards
D) Oxidation occurs at the anode and is where cations move towards
E) Oxidation occurs at the cathode and is where cations move towards

Question 38

A galvanic cell has the overall reaction:
Zn(s) + 2Eu(NO₃)₃(aq) $\rarr$ Zn(NO₃)₂(aq) + 2Eu(NO₃)₂(aq)
Which is the half reaction occurring at the anode

A)NO₃^-(aq) + 4H⁺(aq) + 3e^- $\rarr$ NO(g) + 2H₂O(l)
B)NO₂(g) + H₂O(l) $\rarr$ NO₃^-(aq) + 2H⁺(aq) + e^-
C)Zn(s) $\rarr$ Zn²⁺(aq) + 2e^-
D)Eu³⁺(aq) + e^- $\rarr$ Eu²⁺
E)Zn(s) + 2e^- $\rarr$ Zn²⁺(aq)^-

Question 39

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}&\underline{\mathrm{E}^\circ(V)}\\\mathrm{Al}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(\mathrm{~s}) & -1.66 \\\mathrm{AgBr}(\mathrm{~s})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{~s})+\mathrm{Br}^- & +0.07 \\\mathrm{Sn}^{4+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Sn}^{2+} & +0.14 \\\mathrm{Fe}^{3+}+\mathrm{e}^{-} \rightarrow \mathrm{Fe}^{2+} & +0.77\end{array}$ The strongest reducing agent among those shown above is

A) Fe³⁺.
B) Fe²⁺.
C) Br^-.
D) Al³⁺.
E) Al.

Question 40

Calculate the value of E ^$\circ$ _cell for the following reaction:
2Au(s) + 3Ca²⁺(aq) $\rarr$ 2Au³⁺(aq) + 3Ca(s)

A) -4.37 V
B) -1.37 V
C) -11.6 V
D) 1.37 V
E) 4.37 V

Question 41

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}\mathrm{Cr}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Cr} & \mathrm{E}^{\circ}=-0.74 \mathrm{~V} \\\mathrm{Co}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Co} & \mathrm{E}^{\circ}=-0.28 \mathrm{~V} \\\mathrm{MnO}_{4^{-}}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O} & \mathrm{E}^{\circ}=+1.51 \mathrm{~V}\end{array}$ The weakest reducing agent listed above is

A) Cr³⁺.
B) Cr.
C) Mn²⁺.
D) Co.
E) MnO₄^-.

Question 42

Determine the equilibrium constant (K_eq) at 25 ^$\circ$ C for the reaction Cl₂(g) + 2Br^- (aq) $\leftrightharpoons$ 2Cl^- (aq) + Br₂(l).

A) 1.5 * 10^-10
B) 6.3 * 10⁹
C) 1.3 * 10⁴¹
D) 8.1 * 10⁴
E) 9.8

Question 43

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}\mathrm{Cr}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Cr} & \mathrm{E}^{\circ}=-0.74 \mathrm{~V} \\\mathrm{Co}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Co} & \mathrm{E}^{\circ}=-0.28 \mathrm{~V} \\\mathrm{MnO}_{4^{-}}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O} & \mathrm{E}^{\circ}=+1.51 \mathrm{~V}\end{array}$ The strongest oxidizing agent listed above is

A) Cr³⁺.
B) Cr.
C) Mn²⁺.
D) Co²⁺.
E) MnO₄^-.

Question 44

For the electrochemical cell, Cd(s) | Cd²⁺(aq) || Co²⁺(aq) | Co(s), determine the equilibrium constant (K_eq) at 25 ^$\circ$ C for the reaction that occurs.

A) 1.1 x 10⁴
B) 1.1 x 10^-23
C) 9.4 x 10²²
D) 1.1 x 10²
E) 5.8 x 10¹

Question 45

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}&\underline{\mathrm{E}^\circ(V)}\\\mathrm{Al}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(\mathrm{~s}) & -1.66 \\\mathrm{AgBr}(\mathrm{~s})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{~s})+\mathrm{Br}^- & +0.07 \\\mathrm{Sn}^{4+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Sn}^{2+} & +0.14 \\\mathrm{Fe}^{3+}+\mathrm{e}^{-} \rightarrow \mathrm{Fe}^{2+} & +0.77\end{array}$ The strongest oxidizing agent among those shown above is

A) Fe³⁺.
B) Fe²⁺.
C) Br^-.
D) Al³⁺.
E) Al.

Question 46

Which one of the following reagents is capable of oxidizing Br^- (aq) to Br₂(l) under standard-state conditions

A) I^- (aq)
B) NO₃^- (aq)
C) Ag⁺ (aq)
D) Al³⁺ (aq)
E) Au³⁺ (aq)

Question 47

Consider the following reaction: 2Fe²⁺(aq) + Cu²⁺ $\rarr$ 2Fe³⁺(aq) + Cu.When the reaction comes to equilibrium, what is the cell voltage

A) 0.43 V
B) 1.11 V
C) 0.78 V
D) -0.43 V
E) 0 V

Question 48

For the electrochemical cell, Fe(s) | Fe²⁺(aq) || Cu²⁺(aq) | Cu⁺(aq) | Pt(s), determine the equilibrium constant (K_eq) at 25 ^$\circ$ C for the reaction that occurs.

A) 1.6 x 10^-10
B) 8.6 x 10¹⁹
C) 1.2 x 10^-20
D) 9.3 x 10⁹
E) 1.3 x 10^-5

Question 49

Calculate $\Delta$ G ^$\circ$ for the electrochemical cell Pb(s) | Pb²⁺(aq) || Fe³⁺(aq) | Fe²⁺(aq) | Pt(s).

A) -1.2 x 10² kJ/mol
B) -1.7 x 10² kJ/mol
C) 1.7 x 10² kJ/mol
D) -8.7 x 10¹ kJ/mol
E) -3.2 x 10⁵ kJ/mol

Question 50

Determine the equilibrium constant, K_eq, at 25 ^$\circ$ C for the reaction 2Br^- (aq) + I₂(s) $\leftrightharpoons$ Br₂(l) + 2I^- (aq).

A) 5.7 * 10^-19
B) 18.30
C) 1.7 * 10⁵⁴
D) 1.9 * 10¹⁸
E) 5.7 * 10^-55

Question 51

Which one of the following reagents is capable of oxidizing Cu(s) to Cu²⁺ (1 M)

A) I^- (1 M)
B) Ni(s)
C) Ag⁺ (1 M)
D) Al³⁺ (1 M)
E) H⁺ (1 M)

Question 52

The half-cell reaction for the oxidation of H₂O(l) to O₂(g) is given below.2H₂O(l) $\rarr$ O₂(g) + 4H⁺(aq) + 4e^- Which choice lists all of the following species that can oxidize H₂O to O₂(g) under standard-state conditions
MnO₄^-(aq), Cl₂(g), Pb²⁺(aq), Cl^- (aq), Ag⁺(aq)

A) Cl^-(aq) only
B) Cl₂(g) only
C) Pb²⁺(aq) and Ag⁺(aq)
D) Cl^-(aq) and MnO₄^-(aq)
E) MnO₄^-(aq) and Cl₂(g)

Question 53

Calculate $\Delta$ G ^$\circ$ for the electrochemical cell Fe(s) | Fe²⁺(aq) || Sn⁴⁺(aq) | Sn²⁺(aq) | Pt(s).

A) -5.5 x 10¹ kJ/mol
B) -1.1 x 10² kJ/mol
C) 6.0 x 10¹ kJ/mol
D) 1.1 x 10⁵ kJ/mol
E) 1.2 x 10² kJ/mol

Question 54

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}&\underline{\mathrm{E}^\circ(V)}\\\mathrm{Al}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Al}(\mathrm{~s}) & -1.66 \\\mathrm{Sn}^{4+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Sn}^{2+} & +0.14 \\\mathrm{I}_{2}(\mathrm{s})+2 \mathrm{e}^{-} \rightarrow 2 \mathrm{I}^{-}(\mathrm{aq}) & +0.53\end{array}$ Which is the weakest oxidizing agent in this list

A) Al³⁺(aq)
B) Al(s)
C) I^-(aq)
D) I₂(s)
E) Sn⁴⁺(aq)

Question 55

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}\mathrm{Cr}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Cr} & \mathrm{E}^{\circ}=-0.74 \mathrm{~V} \\\mathrm{Co}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Co} & \mathrm{E}^{\circ}=-0.28 \mathrm{~V} \\\mathrm{MnO}_{4^{-}}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O} & \mathrm{E}^{\circ}=+1.51 \mathrm{~V}\end{array}$ The strongest reducing agent listed above is

A) Cr³⁺.
B) Cr.
C) Mn²⁺.
D) Co.
E) MnO₄^-.

Question 56

Given the following standard reduction potentials, $\begin{array}{ll}\mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{s}) & \mathrm{E}^{0}=0.80 \mathrm{~V} \\\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}(\mathrm{aq})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{s})+2 \mathrm{NH}_{3}(\mathrm{aq}) & \mathrm{E}^{\circ}=0.04 \mathrm{V}\end{array}$ calculate the formation constant of Ag(NH₃)₂⁺ at 25 ^$\circ$ C.

A) 6.1 * 10^-15
B) 1.5 * 10^-13
C) 6.9 * 10¹²
D) 1.6 * 10¹⁴
E) None of these

Question 57

Which one of the following reagents is capable of reducing Cu²⁺(1 M) to Cu(s)

A) I^- (1 M)
B) Ni(s)
C) Al³⁺ (1 M)
D) F^- (1 M)
E) Ag(s)

Question 58

Which one of the following reagents is capable of reducing Fe³⁺ (1 M) to Fe²⁺ (1 M)

A) H₂(1 atm)
B) NO₃^- (1 M)
C) O₂(1 atm)
D) Br^- (1 M)
E) H⁺ (1 M)

Question 59

Given the following standard reduction potentials, $\begin{array}{ll}\mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{s}) & \mathrm{E}^{\circ}=0.80 \mathrm{~V} \\\mathrm{AgCN}(\mathrm{s})+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{s})+\mathrm{CN}^{-}(\mathrm{aq}) & \mathrm{E}^{\circ}=-0.01 \mathrm{~V}\end{array}$ calculate the solubility product of AgCN at 25 ^$\circ$ C.

A) 4.3 * 10^-14
B) 2.3 * 10¹³
C) 2.1 * 10^-14
D) 5.1 * 10¹³
E) None of these

Question 60

Using a table of standard electrode potentials, decide which of the following statements is completely true.

A) Cu²⁺ can oxidize H₂, and Fe can reduce Mn²⁺.
B) Ni²⁺ can oxidize Cu²⁺, and Fe²⁺ can reduce H⁺.
C) Fe²⁺ can oxidize H₂, and Fe²⁺ can reduce Au³⁺.
D) Br₂ can oxidize Ni, and H₂ can reduce Mn²⁺.
E) H⁺ can oxidize Fe, and Ni can reduce Br₂.

Question 61

The half-reaction that occurs at the cathode during electrolysis of an aqueous CuCl₂ solution is

A)Cu⁺ + e^- $\rarr$ Cu.
B)Cu²⁺ + e^- $\rarr$ Cu⁺.
C)2H₂O + 2e^- $\rarr$ H₂ + 2OH^-.
D)Cl₂ + 2e^- $\rarr$ 2Cl^-.
E)2Cl^- $\rarr$ Cl₂ + 2e^-.

Question 62

The half-reaction that occurs at the cathode during electrolysis of an aqueous sodium iodide solution is

A)Na⁺ + e^- $\rarr$ Na.
B)Na $\rarr$ Na⁺ + e^-.
C)2H₂O + 2e^- $\rarr$ H₂ + 2OH^-.
D)I₂ + 2e^- $\rarr$ 2I^-.
E)( $\rarr$ 2I^- $\rarr$ I₂ + 2e^-).

Question 63

If the measured voltage of the cell Zn(s) | Zn²⁺(aq) || Ag⁺(aq) | Ag(s) is 1.37 V when the concentration of Zn²⁺ ion is 0.010 M, what is the Ag⁺ ion concentration

A) 2.5 M
B) 4.0* 10^-9 M
C) 6.2 * 10^-3 M
D) 2.6 * 10^-51 M
E) 6.2 * 10^-5 M

Question 64

For the electrochemical cell Ni(s) | Ni²⁺(1 M) || H⁺(1 M) | H₂(1 atm) | Pt(s), which one of the following changes will cause a decrease in the cell voltage

A) Increase the pressure of H₂ to 2.0 atm.
B) Decrease the mass of the nickel electrode.
C) Lower the pH of the cell electrolyte.
D) Decrease the concentration of Ni²⁺ ion.
E) None of the above.

Question 65

Consider an electrochemical cell based on the spontaneous reaction
2AgCl(s) + Zn(s) $\rarr$ 2Ag(s) + 2Cl^- + Zn²⁺.
If the zinc ion concentration is kept constant at 1 M, and the chlorine ion concentration is decreased from 1 M to 0.001 M, the cell voltage should

A) increase by 0.06 V.
B) increase by 0.18 V.
C) decrease by 0.06 V.
D) decrease by 0.18 V.
E) increase by 0.35 V.

Question 66

Calculate the cell emf for the following reaction at 25 ^$\circ$ C: 2Ag⁺(0.010 M) + H₂(1 atm) $\rarr$ 2Ag(s) + 2H⁺(pH = 10.0)

A) 1.04 V
B) 1.27 V
C) 0.92 V
D) 0.56 V
E) 0.80 V

Question 67

When an aqueous solution of AgNO₃ is electrolyzed, a gas is observed to form at the anode. The gas is

A) H₂.
B) O₂.
C) NO.
D) NO₂.

Question 68

Consider an electrochemical cell involving the overall reaction 2AgBr(s) + Pb(s) $\rarr$ Pb²⁺ + 2Ag(s) + 2Br^-.Each half-reaction is carried out in a separate compartment. The anion included in the lead half-cell is NO₃^-. The cation in the silver half-cell is K⁺. The two half-cells are connected by a KNO₃ salt bridge. If [Pb²⁺] = 1.0 M, what concentration of Br^- ion will produce a cell emf of 0.25 V at 298 K
Given: AgBr(s) + e^- $\rarr$ Ag + Br^-, E ^$\circ$ = +0.07 V.

A) 0.02 M
B) 0.14 M
C) 0.38 M
D) 1.0 M
E) 7.0 M

Question 69

Calculate the cell emf for the following reaction: Cu²⁺(0.10 M) + H₂(1 atm) $\rarr$ Cu(s) + 2H⁺(pH = 3.00)

A) 0.49 V
B) 0.19 V
C) 0.15 V
D) 0.40 V
E) -0.34 V

Question 70

Calculate the minimum voltage required for the electrolysis of 1.0 M NaCl in neutral solution.2H₂O + 2Cl^- (1.0 M) $\rarr$ H₂(1 atm) + Cl₂(1 atm) + 2OH^- (1 * 10^-7 M)

A) 2.19 V
B) 1.78 V
C) 0.41 V
D) -0.41 V
E) -1.78 V

Question 71

Calculate the cell voltage for the following reaction: Cu²⁺ (0.010 M) + H₂(1 atm) $\rarr$ Cu(s) + 2H⁺( pH = 7.0)

A) 0.19 V
B) -0.01 V
C) 0.34 V
D) 0.69 V
E) 0.49 V

Question 72

The measured voltage of a cell in which the following reaction occurs is 0.96 V:
H₂(g, 1.0 atm) + 2Ag⁺(aq, 1.0 M) $\rarr$ 2H⁺(aq, pH
) + 2Ag(s)
Calculate the pH of the H⁺(aq) solution.

A) 1.4
B) 2.7
C) 5.4
D) 7.1
E) 14.9

Question 73

Predict the products of the electrolysis of aqueous aluminum bromide AlBr₃(aq). (Balancing is not required.)

A) Al + Br₂
B) Al + O₂ + H⁺
C) H₂ + OH^- + Br₂
D) H₂ + O₂

Question 74

Which one of the following reactions must be carried out in an electrolytic cell rather than in a galvanic cell

A)Zn²⁺(aq) + Ca(s) $\rarr$ Zn(s) + Ca²⁺(aq)
B)Al³⁺(aq) + 3Br^-(aq) $\rarr$ Al(s) + (3/2)Br₂(l)
C)2Al(s) + 3Fe²⁺(aq) $\rarr$ 2Al³⁺(aq) + 3Fe(s)
D)H₂(g) + I₂(s) $\rarr$ 2H⁺(aq) + 2I^-(aq)
E)Fe²⁺(aq) + Mg(s) $\rarr$ Fe(s) + Mg²⁺(aq)

Question 75

Predict the products of the electrolysis of aqueous potassium chloride KCl(aq).

A) Cl^-(aq) and K(s)
B) Cl₂(g) and K(s)
C) Cl₂(g) and H₂(g) and OH^-(aq)
D) Cl₂(g) and K⁺(aq)
E) Cl^-(aq) and K⁺(aq)

Question 76

The measured voltage of the cell Pt(s) | H₂ (1.0 atm) | H⁺(aq) || Ag⁺(1.0 M) | Ag(s) is 1.02 V at 25 ^$\circ$ C. Calculate the pH of the solution.

A) 1.86
B) 1.69
C) 3.72
D) 3.89
E) 7.43

Question 77

Which one of the following reactions must be carried out in an electrolytic cell rather than in a galvanic cell

A)3Ni²⁺(aq) + 2Cr(s) $\rarr$ 3Ni(s) + 2Cr³⁺(aq)
B)2Ag⁺(aq) + Pb(s) $\rarr$ 2Ag(s) + Pb²⁺(aq)
C)Br₂(l) + 2Cu⁺(aq) $\rarr$ 2Br^-(aq) + Cu²⁺(aq)
D)Cr³⁺(aq) + 3Ag(s) $\rarr$ Cr + 3Ag⁺(aq)
E)2Fe³⁺(aq) + Sn(s) $\rarr$ 2Fe²⁺(aq) + Sn²⁺(aq)

Question 78

The half-reaction occurring at the cathode during electrolysis of an aqueous copper(II) iodide solution is

A)I₂ + 2e^- $\rarr$ 2I^-.
B)Cu $\rarr$ Cu²⁺ + 2e^-.
C)Cu²⁺ + 2e^- $\rarr$ Cu.
D)2I^- $\rarr$ I₂ + 2e^-.
E)2e^- + 2H₂O $\rarr$ H₂ + 2OH^-.

Question 79

Calculate the cell emf for the following reaction at 25 ^$\circ$ C: Ni(s) + 2Cu²⁺(0.010 M) $\rarr$ Ni²⁺(0.0010 M) + 2Cu⁺(1.0 M)

A) 0.40 V
B) -0.43 V
C) 0.43 V
D) 0.34 V
E) 0.37 V

Question 80

For the electrochemical cell Pt(s) | H₂(1 atm) | H⁺(1 M) || Cu²⁺(1 M) | Cu(s), which one of the following changes will cause an increase in the cell voltage

A) Lower the H₂(g) pressure.
B) Increase the size/mass of the copper electrode.
C) Lower the H⁺(aq) concentration.
D) Decrease the concentration of Cu²⁺ ion.
E) None of the above.