Deck 17: Electrochemistry

Question 1

Using the reduction half-reactions,write an overall reaction in the direction that is spontaneous.Calculate E°.
$\begin{array}{ll}\mathrm{AgI}(s)+e^{-} \rightarrow \mathrm{Ag}(s)+\mathrm{I}-(a q) & E_{\mathrm{red}}^{0}=-0.152 \mathrm{~V} \\\mathrm{Co}^{3+}(a q)+e^{-} \rightarrow \mathrm{Co}^{2+}(a q) & E_{\mathrm{red}}^{\circ}=+1.953 \mathrm{~V}\end{array}$

A) Co²⁺(aq)+ AgI(s)? Co³⁺(aq)+ Ag(s)+ I?(aq)E° = ?2.105 V
B) Co²⁺(aq)+ Ag(s)+ I?(aq)? Co³⁺(aq)+ AgI(s)E° = ?1.801 V
C) Co³⁺(aq)+ Ag(s)+ I?(aq)? Co²⁺(aq)+ AgI(s)E° = +1.801 V
D) Co³⁺(aq)+ Ag(s)+ I?(aq)? Co²⁺(aq)+ AgI(s)E° = +2.105 V
E) Co³⁺(aq)+ AgI(s)? Co²⁺(aq)+ Ag(s)+ I?(aq)E° = ?2.105 V

Answer 1

Co³⁺(aq)+ Ag(s)+ I?(aq)? Co²⁺(aq)+ AgI(s)E° = +2.105 V

Question 2

Use the standard reduction potentials below to determine which element or ion is the best reducing agent. $\begin{array}{ll}\mathrm{NO}_{3}^{-}(a q)+4 \mathrm{H}^{+}(a q)+3 e^{-} \rightarrow \mathrm{NO}(g)+2 \mathrm{H}_{2} \mathrm{O}(t) & E^{\circ}=+0.955 \mathrm{~V} \\\mathrm{Pd}^{2+}(a q)+2 \mathrm{e}^{-} \rightarrow \mathrm{Pd}(s) & E^{\circ}=+0.90 \mathrm{~V} \\2 \mathrm{H}^{+}(a q)+2 \mathrm{e}^{-} \rightarrow \mathrm{H}_{2}(g) & E^{\circ}=0.00 \mathrm{~V}\end{array}$

A) Pd²⁺(aq)
B) Pd(s)
C) H⁺(aq)
D) H₂(g)
E) NO₃^-(aq)

Answer 2

H₂(g)

Question 3

Given the following two half-reactions,write the overall balanced reaction in the direction in which it is spontaneous and calculate the standard cell potential.
$\begin{array}{ll}\mathrm{Ga}^{3+}(a q)+3 e^{-} \rightarrow \mathrm{Ga}(s) & E_{\mathrm{red}}^{\circ}=-0.53 \mathrm{~V} \\\mathrm{Sn}^{4+}(a q)+2 e^{-} \rightarrow \operatorname{Sn}^{2+}(a q) & E_{o x}^{\circ}=+0.15 \mathrm{~V} \\\end{array}$

A) 2Ga³⁺(aq)+ 3Sn²⁺(aq)? 2Ga(s)+ 3Sn⁴⁺(aq)E° = +0.68 V
B) 3Ga³⁺(aq)+ 2Sn²⁺(aq)? 3Ga(s)+ 2Sn⁴⁺(aq)E° = -1.89 V
C) 2Ga(s)+ 3Sn⁴⁺(aq)? 2Ga³⁺(aq)+ 3Sn²⁺(aq)E° = +0.68 V
D) 3Ga(s)+ 2Sn⁴⁺(aq)? 3Ga³⁺(aq)+ 2Sn²⁺(aq)E° = +0.38 V
E) 2Ga(s)+ 3Sn⁴⁺(aq)? 2Ga³⁺(aq)+ 3Sn²⁺(aq)E° = +1.89 V

Answer 3

2Ga(s)+ 3Sn⁴⁺(aq)? 2Ga³⁺(aq)+ 3Sn²⁺(aq)E° = +0.68 V

Question 4

Write a balanced chemical equation for the overall reaction represented below. Pt | Fe²⁺,Fe³⁺ || Cl− | AgCl | Ag

A) AgCl(s)+ Fe³⁺(aq)+ 2e− → Ag(s)+ Fe²⁺(aq)+ Cl−(aq)
B) AgCl(s)+ Fe³⁺(aq)→ Ag(s)+ Fe²⁺(aq)+ Cl−(aq)
C) AgCl(s)+ Fe²⁺(aq)→ Ag(s)+ Fe³⁺(aq)+ Cl−(aq)
D) Ag(s)+ Fe³⁺(aq)+ Cl−(aq)→ AgCl(s)+ Fe²⁺(aq)
E) Ag(s)+ Fe²⁺(aq)+ Cl−(aq)→ AgCl(s)+ Fe³⁺(aq)

Question 5

Write a balanced net ionic equation for the overall reaction represented by the cell notation below. Ag | AgI | I^- || Fe²⁺,Fe³⁺ | Pt

A) Fe³⁺(aq)+ Ag(s)+ I^-(aq)→ Fe²⁺(aq)+ AgI(s)
B) Fe²⁺(aq)+ Ag(s)+ I^-(aq)→ Fe³⁺(aq)+ AgI(s)
C) Fe³⁺(aq)+ AgI(s)→ Fe²⁺(aq)+ Ag(s)+ I^-(aq)
D) Fe²⁺(aq)+ AgI(s)→ Fe³⁺(aq)+ Ag(s)+ I^-(aq)
E) Fe³⁺(aq)+ 2I^-(aq)→ Fe²⁺(aq)+ I₂(s)

Question 6

Given the following half-reactions, Pb(s)+ 2I−(aq)→ PbI₂(s)+ 2e−
I₂(aq)+ 2e− → 2I−(aq)
Write the balanced overall reaction.

A) Pb(s)+ I₂(aq)+ 2e− → PbI (s)+ I−(aq)
B) Pb(s)+ I₂(aq)→ PbI₂(s)
C) Pb(s)+ Cl₂(aq)→ Pb²⁺(aq)+ 2I−(aq)
D) 2Pb(s)+ 4e− → 2PbI(s)+ I₂(aq)
E) Pb(s)+ e− + 2I−(aq)→ PbI₂(aq)

Question 7

What is a correct cell notation for a voltaic cell based on the reaction below? Cu²⁺(aq)+ Pb(s)+ SO₄^2-(aq)→ Cu(s)+ PbSO₄(s)

A) Pb | PbSO₄ || Cu²⁺ || Cu
B) Cu | Cu²⁺ || SO₄^2- | PbSO₄ | Pb
C) Cu | Cu²⁺,SO₄^2- | PbSO₄ | Pb
D) Cu | Cu²⁺,SO₄^2- || PbSO₄ || Pb
E) Pb | PbSO₄ | SO₄^2- || Cu²⁺ || Cu

Question 8

Which of the following species are likely to behave as oxidizing agents: Li(s),H₂(g),MnO₄^-(aq),and Cl^-(aq)?

A) Li(s)only
B) MnO₄^-(aq)only
C) H₂(g)and Cl^-(aq)
D) Li(s)and MnO₄^-(aq)
E) Cl^-(aq)only

Question 9

The following reaction occurs spontaneously. 2 Fe(s)+ 3 Cl₂(aq)→ 2 Fe³⁺(aq)+ 6 Cl^-(aq)
Write the balanced reduction half-reaction.

A) Fe(s)→ Fe³⁺(aq)+ e^-
B) Fe(s)+ 3 e^- → Fe³⁺(aq)
C) Fe(s)+ 3/2 Cl₂(aq)→ FeCl₃(aq)
D) Cl₂(aq)→ 2 Cl^-(aq)+ 2 e^-
E) Cl₂(aq)+ 2 e^- → 2 Cl^-(aq)

Question 10

Write the overall chemical reaction and calculate E° for the following reduction and oxidation half-reactions.
2H⁺(aq)+ 2e? ? H₂(g) ${E}_{\text {red }}^{0}$ = 0.000 V
Zn(s)? Zn²⁺(aq)+ 2e? $E_{o x}^{\circ}$ = +0.762 V

A) Zn²⁺(aq)+ H₂(g)? Zn(s)+ 2H⁺(aq)E° = +0.381 V
B) Zn²⁺(aq)+ H₂(g)? Zn(s)+ 2H⁺(aq)E° = ?0.762 V
C) Zn(s)+ 2H⁺(aq)? Zn²⁺(aq)+ H₂(g)E° = +0.762 V
D) Zn(s)+ 2H⁺(aq)? Zn²⁺(aq)+ H₂(g)E° = ?0.762 V
E) Zn(s)+ 2H⁺(aq)? Zn²⁺(aq)+ H₂(g)E° = ?0.381 V

Question 11

Which species is the best reducing agent?

A) Sodium ion
B) Sulfide ion
C) Chlorine
D) Sodium metal
E) Silver metal

Question 12

The following reaction occurs spontaneously. 2Al(s)+ 6H⁺(aq)→ 2Al³⁺(aq)+ 3H₂(g)
Write the balanced oxidation half-reaction.

A) Al(s)→ Al³⁺(aq)+ 3e−
B) Al³⁺(aq)+ 3e− → Al(s)
C) H₂(g)→ 2H⁺(aq)+ 2e−
D) 2H⁺(aq)+ 2e− → H₂(g)
E) 2H⁺(aq)→ H₂(g)+ 2e−

Question 13

Using the reduction half-reactions,write an overall reaction in the direction that it is spontaneous.Calculate E°. $\begin{array}{l}\mathrm{MnO}_{4}-(a q)+8 \mathrm{H}^{+}(a q)+5 e^{-} \rightarrow 2 \mathrm{Mn}^{2+}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l) & E_{\text {red }}^{\circ}=+1.512 \mathrm{~V}\\\mathrm{Fe}^{3+}(a q)+e^{-} \rightarrow \mathrm{Fe}^{2+}(a q) &E_{\mathrm{red}}^{\circ}=+0.769 \mathrm{~V}\end{array}$

A) 5Fe³⁺(aq)+ Mn²⁺(aq)+ 4H₂O(l)? 5Fe²⁺(aq)+ MnO₄?(aq)+ 8H⁺(aq)E° = +2.333 V
B) 5Fe²⁺(aq)+ Mn²⁺(aq)+ 4H₂O(l)? 5Fe³⁺(aq)+ MnO₄?(aq)+ 8H⁺(aq)E° = ?0.743 V
C) MnO₄?(aq)+ 5Fe²⁺(aq)? Mn²⁺(aq)+ 5Fe³⁺(aq)E° = ?2.281 V
D) MnO₄?(aq)+ 8H⁺(aq)+ 5Fe²⁺(aq)? Mn²⁺(aq)+ 5Fe³⁺(aq)+ 4H₂O(l)E° = +0.743 V
E) MnO₄?(aq)+ 8H⁺(aq)+ 5Fe³⁺(aq)? Mn²⁺(aq)+ 5Fe²⁺(aq)+ 4H₂O(l)E° = +2.281 V

Question 14

What is the correct cell notation for the reaction below? Cd²⁺(aq)+ Ni(s)→ Cd(s)+ Ni²⁺(aq)

A) Cd²⁺ | Cd || Ni | Ni²⁺
B) Cd | Cd²⁺ || Ni²⁺ | Ni
C) Ni | Ni²⁺ || Cd²⁺ | Cd
D) Ni | Cd²⁺ || Ni²⁺ | Cd
E) Cd²⁺ | Cd || Ni | Ni²⁺..

Question 15

Write a balanced chemical equation for the overall reaction represented below. Cu | Cu²⁺ || Cl− | Hg₂Cl₂ | Hg

A) 2Hg(l)+ Cu²⁺(aq)+ 2Cl−(aq)→ Hg₂Cl₂(s)+ Cu(s)
B) Hg₂Cl₂(s)+ Cu(s)→ 2Hg(l)+ Cu²⁺(aq)+ 2Cl−(aq)
C) Hg₂Cl₂(s)→ 2Hg(l)+ Cl₂(aq)
D) Hg₂Cl₂(s)+ Cu(s)→ 2Hg(l)+ Cu²⁺(aq)+ Cl₂(aq)
E) 2Hg(l)+ Cl₂(aq)→ Hg₂Cl₂(s)

Question 16

Given the following half-reactions, 2IO₃−(aq)+ 12H⁺(aq)+ 10e− → I₂(s)+ 6H₂O(l)
Fe²⁺(aq)→ Fe³⁺(aq)+ e−
Write the balanced overall reaction.

A) 2IO₃−(aq)+ Fe²⁺(aq)→ I₂(s)+ Fe³⁺(aq)
B) 2IO₃−(aq)+ 10Fe²⁺(aq)→ I₂(s)+ 10Fe³⁺(aq)
C) 2IO₃−(aq)+ 12H⁺(aq)+ Fe²⁺(aq)→ FeI₂(s)+ 6H₂O(l)
D) 2IO₃−(aq)+ 12H⁺(aq)+ Fe²⁺(aq)→ I₂(s)+ Fe³⁺(aq)+ 6H₂O(l)
E) 2IO₃−(aq)+ 12H⁺(aq)+ 10Fe²⁺(aq)→ I₂(s)+ 10Fe³⁺(aq)+ 6H₂O(l)

Question 17

The standard reduction potential, ${E}_{\text {red }}^{0}$ ,of Zn²⁺(aq)is ?0.762 V.Write the equation for the standard oxidation potential.What is the value of $E_{o x}^{\circ}$ ?

A) Zn²⁺(aq)+ 2e? ? Zn(s) $E_{o x}^{\circ}$ = ?0.762 V
B) Zn²⁺(aq)? Zn(s)+ 2e? $E_{o x}^{\circ}$ = +0.762 V
C) Zn²⁺(aq)? Zn(s)+ 2e? $E_{o x}^{\circ}$ = ?0.762 V
D) Zn(s)+ 2e? ? Zn²⁺(aq) $E_{o x}^{\circ}$ = ?0.762 V
E) Zn(s)? Zn²⁺(aq)+ 2e? $E_{o x}^{\circ}$ = +0.762 V

Question 18

Which species is the best oxidizing agent?

A) Bromine
B) Sodium ion
C) Potassium metal
D) Fluoride ion
E) Carbon dioxide

Question 19

Which of the following species are reducing agents: K,H⁺,MnO₄−,Cl₂,Sn⁴⁺?

A) K only
B) K and Co³⁺
C) H⁺ and Sn⁴⁺
D) MnO₄− and Cl₂
E) Cl₂ and Sn⁴⁺

Question 20

The standard oxidation potential, $E_{o x}^{\circ}$ ,of Cu(s)is ?0.339 V.The oxidation product is the copper(II)ion.Write the equation for the standard reduction potential.What is the value of the standard reduction potential, ${E}_{\text {red }}^{0}$ ?

A) Cu²⁺(aq)? Cu(s)+ 2e? ${E}_{\text {red }}^{0}$ = ?0.339 V
B) Cu²⁺(aq)+ 2e? ? Cu(s) ${E}_{\text {red }}^{0}$ = +0.339 V
C) Cu(s)+ 2e? ? Cu²⁺(aq) ${E}_{\text {red }}^{0}$ = ?0.339 V
D) Cu(s)? Cu²⁺(aq)+ 2e? ${E}_{\text {red }}^{0}$ = +0.339 V
E) Cu(s)+ 2e? ? Cu²⁺(aq) ${E}_{\text {red }}^{0}$ = +0.339 V

Question 21

The standard reduction potentials for F₂(g)and Br₂(l)are +2.889 V and 1.077 V,respectively.Write the chemical equation and calculate E° for a voltaic cell based on fluorine and bromine.

A) F₂(g)+ 2Br−(aq)→ 2F−(aq)+ Br₂(g)E° = +1.812 V
B) F₂(g)+ Br₂(g)→ 2F−(aq)+ 2Br−(aq)E° = −1.812 V
C) F₂(g)+ Br₂(g)→ 2F−(aq)+ 2Br−(aq)E° = +1.812 V
D) 2F−(aq)+ 2Br−(aq)→ F₂(g)+ Br₂(g)E° = +1.812 V
E) Br₂(g)+ 2F−(aq)→ 2Br−(aq)+ F₂(g)E° = −1.812 V

Question 22

The cell voltage,E°,is ____ for a reaction taking place in a voltaic cell.

A) reductive
B) oxidative
C) negative
D) zero
E) positive

Question 23

In an electrochemical cell,if E > E° then

A) Q > 1.
B) Q < 1.
C) n = 1.
D) F > 9.648 × 10⁴.
E) the system has reached equilibrium.

Question 24

Use the standard reduction potentials below to determine which of the following metals can be oxidized by 1.0 M
HCl: Al,Zn,Sn,Cu.
$\begin{array}{l}\mathrm{Al}^{3+}(a q)+3 e-\rightarrow \mathrm{Al}(s) & \bar{E}_{1 e d}^{0}=-1.68 \mathrm{~V}\\\mathrm{Zn}^{2+}(a g)+2 e^{-} \rightarrow \mathrm{Zn}(s) & E_{\circ \mathrm{z}}=-0.762 \mathrm{~V}\\\mathrm{Sn}^{2+}(a q)+2 e-\underline{\mathrm{Sn}}(s) & E_{o \mathrm{z}}^{0}=-0.141 \mathrm{~V}\\\mathrm{Cu}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Cu}(s) &E_{\mathrm{red}=+0.339 \mathrm{~V}}^{\rho}\end{array}$

A) Al only
B) Cu only
C) Al and Cu
D) Zn and Sn
E) Al,Zn,and Sn

Question 25

Calculate the equilibrium constant for the following reaction at 25°C, 2IO₃^-(aq)+ 5Hg(l)+ 12H⁺(aq)? I₂(s)+ 5Hg²⁺(aq)+ 6H₂O(l) Given the following thermodynamic information.(R = 8.31 J/K?mol,F = 96480 C/mol e?)z
$\begin{array}{ll}\mathrm{IO}_{3}{ }^{-}(a q)+6 \mathrm{H}^{+}(a q)+5 e^{-} \rightarrow \mathrm{I}_{2}(s)+3 \mathrm{H}_{2} \mathrm{O}(l) & E^{\circ}=+1.20 \mathrm{~V} \\\mathrm{Hg}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Hg}(l) & E^{\circ}=+0.86 \mathrm{~V}\end{array}$

A) 3 × 10^-58
B) 6 × 10⁵
C) 3 × 10¹¹
D) 6 × 10²⁸
E) 3 × 10⁵⁷

Question 26

What is the relationship between ?G° and E°?

A) ?G° = FE°
B) ?G° = ?nFE°
C) $\Delta G^{\circ}=\frac{E^{\circ}}{F}$
D) $\Delta G^{\circ}=\frac{n E^{\circ}}{F}$
E) $\Delta G^{\circ}=-\frac{n E^{\circ}}{F}$

Question 27

The overall chemical reaction for the electrolytic decomposition of water is 2H₂O → O₂(g)+ 2H₂(g)
What is the reduction half-reaction?

A) 2H⁺(aq)→ H₂(g)+ 2e−
B) H₂(g)+ 2OH−(aq)+ 2e− → 2H₂O(l)
C) 2H₂O(l)+ 2e− → H₂(g)+ 2OH−(aq)
D) O₂(g)+ 4H⁺(aq)+ 4e− → 2H₂O(l)
E) H₂O(l)→ H₂(g)+ O²⁻(aq)+ 2e−

Question 28

For a spontaneous reaction,at constant pressure

A) ΔG° > 0 and E° > 0.
B) ΔG° > 0 and E° < 0.
C) ΔG° < 0 and E° > 0.
D) ΔG° < 0 and E° < 0.
E) ΔG° = 0 and E° = 0.

Question 29

A voltaic cell is based upon the following overall reaction: 2Ag⁺(aq)+ Sn(s)→ 2Ag(s)+ Sn²⁺(aq)
Where E° = +0.940 V.Calculate the equilibrium constant at 25°C? (R = 8.31 J/K⋅mol,F = 96480 C/mol e−)

A) 6.1 × 10¹²
B) 8.0 × 10¹⁵
C) 1.6 × 10²³
D) 6.5 × 10³¹
E) 9.1 × 10⁴³

Question 30

Calculate E° for the electrochemical cell below, Ag | AgCl| Cl^- || Cu²⁺ | Cu
Given the following standard reduction potentials.
$\begin{array}{ll}\mathrm{Cu}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Cu}(s) & E^{\circ}=+0.337 \mathrm{~V} \\\mathrm{AgCl}(\mathrm{s})+e^{-} \rightarrow \mathrm{Ag}(\mathrm{s})+\mathrm{Cl}^{-}(a q) & E^{\circ}=+0.222 \mathrm{~V}\end{array}$

A) -0.115 V
B) -0.107 V
C) +0.115 V
D) +0.452 V
E) +0.559 V

Question 31

Calculate E° for the electrochemical cell below, Pb |PbCl₂ | Cl^- || Fe³⁺,Fe²⁺ | Pt Given the following reduction half-reactions.
$\begin{array}{ll}\mathrm{Pb}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Pb}(s) & E^{\circ}=-0.126 \mathrm{~V} \\\mathrm{PbCl}_{2}(s)+2 e^{-} \rightarrow \mathrm{Pb}(s)+2 \mathrm{Cl}^{-}(a q) & E^{\circ}=-0.267 \mathrm{~V} \\\mathrm{Fe}^{3+}(a q)+e^{-} \rightarrow \mathrm{Fe}^{2+}(a q) & E^{\circ}=+0.771 \mathrm{~V} \\\mathrm{Fe}^{2+}(a q)+e^{-} \rightarrow \mathrm{Fe}(s) & E^{\circ}=-0.44 \mathrm{~V}\end{array}$

A) -0.504 V
B) -0.062 V
C) +0.504 V
D) +1.038 V
E) +1.604 V

Question 32

Which of the following half-reactions has been assigned a standard reduction potential of 0.00 V?

A) 2H⁺(aq)+ 2e− → H₂(g)
B) Ag⁺(aq)+ e− → Ag(s)
C) Hg₂Cl₂(s)+ 2e− → 2Hg(l)+ 2Cl−(aq)
D) Au³⁺(aq)+ 3e− → Au(s)
E) Cu²⁺(aq)+ 2e− → Cu(s)

Question 33

Calculate ?G° for the disproportionation reaction of Cu⁺ at 25°C, 2Cu⁺(aq)? Cu²⁺(aq)+ Cu(s) Given the following thermodynamic information.(R = 8.31 J/K?mol,F = 96480 C/mol e?)
$\begin{array}{lccc} \mathrm{Cu}^{+}(a q)+e^{-} \rightarrow \mathrm{Cu}(s) & E^{\circ}=+0.518 \mathrm{~V} \\ \mathrm{Cu}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Cu}(s)&E^{\circ}=+0.337 \mathrm{~V} \\\end{array}$

A) -165 kJ
B) -135 kJ
C) -34.9 kJ
D) +17.5 kJ
E) +135 kJ

Question 34

Calculate E for the following electrochemical cell at 25°C, Cu | Cu²⁺ (0.100 M)|| Zn²⁺ (0.0750 M)| Zn
If E° (Cu²⁺)= +0.339 V and E° (Zn²⁺)= −0.762 V.(R = 8.31 J/K⋅mol,F = 96480 C/mol e−)

A) −1.105 V
B) −0.919 V
C) −0.486 V
D) −0.259 V
E) +0.486 V

Question 35

Calculate E° for an electrochemical cell based on the following overall reaction: 2H⁺(aq)+ Cd(s)? H₂(g)+ Cd²⁺(aq)
If ${E}_{\text {red }}^{o}$ (H⁺)= 0.000 V and ${E}_{\text {red }}^{o}$ (Cd²⁺)= ?0.402 V.

A) ?0.402 V
B) ?0.201 V
C) 0.000 V
D) +0.201 V
E) +0.402 V

Question 36

A voltaic cell is based upon the half-reactions below. $\begin{array}{lccc}\mathrm{Pb}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Pb}(s) & E^{\circ}=-0.127 \mathrm{~V}\\\mathrm{Cd}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Cd}(s) & E^{\circ}=-0.402 \mathrm{~V} \\\end{array}$

Calculate the equilibrium constant for the overall chemical reaction at 25°C.(R = 8.31 J/K?mol,F = 96480 C/mol e?)

A) 1.3 × 10²
B) 4.4 × 10⁴
C) 2.0 × 10⁹
D) 3.9 × 10¹⁸
E) 1.3 × 10²¹

Question 37

What is the correct form of the Nernst equation?

A) $E^{\circ}=E-\frac{R T}{n F} \ln Q$
B) $E=E^{\circ}-\frac{R T}{n F} \ln Q$
C) $E=E^{\circ}-\frac{n F}{R T} \ln Q$
D) $G=E^{\circ}+\frac{R T}{n F} \ln Q$
E) $G^{\circ}=G-\frac{R T}{n F} \ln Q$

Question 38

Calculate ΔG° for a voltaic cell with E° = +0.24 V if the overall reaction involves a 3 electron reduction.(R = 8.31 J/K⋅mol,F = 96480 C/mol e−)

A) −69 kJ
B) −23 kJ
C) −0.83 kJ
D) + 220 kJ
E) +580 kJ

Question 39

What is the relationship between E° and the equilibrium constant,K?

A) $E^{\circ}=\frac{R T}{n F} \ln K$
B) $E^{\circ}=\frac{n F}{R T} \ln K$
C) E° = RT ln K
D) E° = ?RT ln K
E) $E^{\circ}=\frac{n F}{R T} \log K$

Question 40

Given the following standard reduction potentials, $\begin{array}{ll}\mathrm{Pb}^{2+}(a q)+2 e^{-} \rightarrow \mathrm{Pb}(s) & E^{\circ}=-0.126 \mathrm{~V} \\\mathrm{PbSO}_{4}(s)+2 e^{-} \rightarrow \mathrm{Pb}(\mathrm{s})+\mathrm{SO}_{4}^{2-}(a q) & E^{\circ}=-0.355 \mathrm{~V}\end{array}$
Determine K_sp for PbSO₄(s)at 25°C.(R = 8.31 J/K?mol,F = 96480 C/mol e?)

A) 3.4 × 10^-28
B) 1.8 × 10^-8
C) 5.6 × 10^-5
D) 5.6 × 10⁷
E) 2.9 × 10³⁷

Question 41

Al³⁺ is reduced to Al(s)at an electrode surface.If a current of 25 amperes is maintained for 8.0 hours,what mass of aluminum is deposited on the electrode? Assume 100% current efficiency.

A) 0.019 g
B) 2.5 g
C) 44 g
D) 67 g
E) 2.0 × 10² g

Question 42

If current is passed in an electrolytic cell containing sodium chloride dissolved in water,what is the product at the cathode?

A) H⁺
B) NaCl(s)
C) H₂(g)
D) Cl₂(g)
E) O₂(g)

Question 43

What charge,in coulombs,is required to deposit 1.5 g Mg(s)from a solution of Mg²⁺(aq)? (F = 96480 C/mol e−)

A) 4.1 × 10² C
B) 6.0 × 10³ C
C) 1.2 × 10⁴ C
D) 2.9 × 10⁵ C
E) 3.1 × 10⁶ C

Question 44

For the lead storage battery,the products of the discharge reaction are

A) Pb at the anode,H₂O at the cathode.
B) H₂SO₄ at the anode,H₂O at the cathode.
C) PbSO₄ at both the anode and cathode.
D) Pb at the cathode and PbO₂ at the anode.
E) Pb at both the anode and cathode.

Question 45

What is the pH of the solution at the cathode if E = -0.362 V for the following electrochemical cell at 25°C? Pt | H₂(1.0 atm)| H⁺(1.00 M)|| H⁺(aq)| H₂(1.0 atm)| Pt

A) 1.77
B) 3.06
C) 6.11
D) 7.89
E) 12.23

Question 46

Calculate E for the following electrochemical cell at 25°C
Pt | Fe³⁺(0.100 M),Fe²⁺(0.040 M)|| Cl^-(0.50 M)| AgCl | Ag
Given the following standard reduction potentials.
$\begin{array}{ll}\left.\mathrm{AgCl}(s)+e^{-} \rightarrow \mathrm{Ag}^{2+}\right)+\mathrm{Cl}^{-}(a q) & E^{\circ}=+0.222 \mathrm{~V} \\\mathrm{Fe}^{3+}(a q)+e^{-} \rightarrow \mathrm{Fe}^{2+}(a q) & E^{\circ}=+0.771 \mathrm{~V}\end{array}$

A) -1.034 V
B) -0.590 V
C) -0.508 V
D) -0.555 V
E) +1.034 V

Question 47

What charge (in Coulombs)is required to oxidize 1.0 g of silver to silver(I)ions? (F = 96480 C/mol e−)

A) 1.0 × 10−⁵ C
B) 1.1 × 10−³ C
C) 3.1 × 10−¹ C
D) 6.1 × 10¹ C
E) 8.9 × 10² C

Question 48

Calculate E for the following electrochemical cell at 25°C, Pt | H₂(g)(1.0 atm)| H⁺ (0.010 M)|| Ag⁺ (0.020 M)| Ag
If E° (H⁺)= +0.000 V and E° (Ag⁺)= 0.799 V.

A) +0.275 V
B) +0.799 V
C) +0.817 V
D) +0.911 V
E) +1.01 V

Question 49

What concentration of Ag⁺ is present in the following electrochemical cell if E = −0.683 V and E° (Ag⁺)= +0.799 V at 25°C? Ag | Ag⁺ (? M)|| H⁺ (1.0 M)| H₂ (1.0 atm)| Pt

A) 9.3 × 10−²⁶ M
B) 8.1 × 10−⁴ M
C) 1.1 × 10−² M
D) 9.1 × 10−¹ M
E) 9.1 × 10¹ M

Question 50

One kind of battery used in watches contains mercury(II)oxide.As current flows,the mercury(II)oxide is reduced to mercury. HgO(s)+ H₂O(l)+ 2e^- → Hg(l)+ 2OH^-(aq)
If 2.3 × 10^-5 amperes flows continuously for 1200 days,what mass of Hg(l)is produced? (F = 96480 C/mol e−)

A) 2.5 g
B) 5.0 g
C) 9.9 g
D) 13 g
E) 15 g

Question 51

An electrolytic cell is used to plate silver from a silver nitrate solution onto an electrode.How much time (in seconds)is required to deposit 8.0 g of silver if the current is kept constant at 5.0 amperes? Assume 100% current efficiency.(F = 96480 C/mol e−)

A) 1.7 × 10² s
B) 1.4 × 10³ s
C) 2.5 × 10⁴ s
D) 5.9 × 10⁴ s
E) 2.6 × 10⁵ s

Question 52

A baby's spoon with an area of 6.25cm² is plated with silver from a silver nitrate solution using a current of 2.00 A for two hours and 25 minutes.What is the thickness of the silver plate formed if the current efficiency is 82%? (F = 96480 C/mol e−)(d _Ag= 10.5 g/cm³)

A) 0.300 cm
B) 0.243 cm
C) 0.366 cm
D) 0.166 cm
E) 5.34 × 10−² cm