Deck 18: Electrochemistry

Question 1

What is the reduction half reaction for the following chemical reaction in a basic solution? ClO^-(aq)+ Cr(OH)₄^-(aq)→ CrO₄^2-(aq)+ Cl^-(aq)

A)ClO^-(aq)+ 2 H⁺(aq)+ 2e^- → Cl^-(aq)+ H₂O(l)
B)ClO^-(aq)+ H₂O(l)+ 2e^- → Cl^-(aq)+ 2 OH^-(aq)
C)Cr(OH)₄^-(aq)+ 4 OH^-(aq)→ CrO₄^2-(aq)+ 4 H₂O(l)+ 3e^-
D)Cr(OH)₄^-(aq)→ CrO₄^2-(aq)+ 4 H⁺(aq)+ 3e^-

Answer 1

ClO^-(aq)+ H₂O(l)+ 2e^- → Cl^-(aq)+ 2 OH^-(aq)

Question 2

Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in an acidic solution.

A)2
B)4
C)5
D)7

Answer 2

4

Question 3

What species is oxidized in the reaction: CuSO₄(aq)+ Mg(s)→ MgSO₄(aq)+ Cu(s)?

A)CuSO₄ (aq)
B)Mg (s)
C)MgSO₄ (aq)
D)Cu (s)

Answer 3

Mg (s)

Question 4

For a galvanic cell,the cathode has a ________ sign and is the site of ________.

A)negative,oxidation
B)negative,reduction
C)positive,oxidation
D)positive,reduction

Question 5

Determine the number of water molecules necessary to balance the following chemical equation. Cr₂O₇^2-(aq)+ Cl^-(aq)+ H⁺(aq)→ Cr³⁺(aq)+ Cl₂(g)+ ________ H₂O(l)

A)3
B)5
C)7
D)14

Question 6

What is the molarity of a potassium triiodide solution,KI₃(aq),if 30.00 mL of the solution is required to completely react with 25.00 mL of a 0.200 M thiosulfate solution,Na₂S₂O₃(aq)? The chemical equation for the reaction is:

A)0.0833 M
B)0.120 M
C)0.167 M
D)0.333 M

Question 7

What are the coefficients in front of NO₃^-(aq)and Cu(s)when the following redox equation is balanced in an acidic solution: ________ NO₃^-(aq)+ ________ Cu(s)→ ________ NO(g)+ ________ Cu²⁺(aq)?

A)2,3
B)2,6
C)3,4
D)3,6

Question 8

Based on the balanced chemical equation shown below,determine the mass percent of Fe³⁺ in a 0.6450 gram sample of iron ore,if 22.40 mL of a 0.1000 M stannous chloride,SnCl₂(aq),solution is required to completely react with the Fe³⁺ present in the ore sample.The chemical equation for the reaction is: 2 Fe³⁺(aq)+ Sn²⁺(aq)→ 2 Fe²⁺(aq)+ Sn⁴⁺(aq).

A)6.196%
B)9.697%
C)19.40%
D)38.79%

Question 9

Based on the balanced chemical equation shown below,determine the molarity of a solution containing Fe²⁺(aq),if 40.00 mL of the Fe²⁺(aq)solution is required to completely react with 30.00 mL of a 0.125 M potassium bromate,KBrO₃(aq),solution.The chemical equation for the reaction is: 6 Fe²⁺(aq)+ BrO₃^-(aq)+ 6 H⁺(aq)→ 6 Fe³⁺(aq)+ Br^-(aq)+ 3 H₂O(l).

A)0.0156 M
B)0.0938 M
C)0.562 M
D)1.00 M

Question 10

In a galvanic cell,the half-reaction H₂(g)+ 2 OH^-(aq)→ 2 H₂O(l)+ 2 e^- is

A)an oxidation half-reaction and occurs at the anode.
B)an oxidation half-reaction and occurs at the cathode.
C)a reduction half-reaction and occurs at the anode.
D)a reduction half-reaction and occurs at the cathode.

Question 11

According to the balanced equation shown below,1.00 mole of oxalic acid,H₂C₂O₄,reacts with ________ moles of permanganate ion,MnO₄^-. 5 H₂C₂O₄(aq)+ 2 MnO₄^-(aq)+ 6 H⁺(aq)→ 10 CO₂(g)+ 2 Mn²⁺(aq)+ 8 H₂O(l)

A)0.400
B)1.00
C)2.00
D)2.25

Question 12

During an electrochemical reaction,electrons move through the external circuit toward the ________ and positive ions in the cell move toward the ________.

A)anode,anode
B)anode,cathode
C)cathode,anode
D)cathode,cathode

Question 13

Which of the following terms can be used to describe an electrochemical cell in which a spontaneous chemical reaction generates an electric current? I.an electrolytic cell
II.a galvanic cell
III.a voltaic cell

A)only I
B)only II
C)only III
D)II and III

Question 14

What is the oxidation half reaction in the following chemical reaction? Cr₂O₇^2-(aq)+ 6 Cl^-(aq)+ 14 H⁺(aq)→ 2 Cr³⁺(aq)+ 3 Cl₂(aq)+ 7 H₂O(l)

A)Cr₂O₇^2-(aq)+ 14 H⁺(aq)+ 6e^- → 2 Cr³⁺(aq)+ 7 H₂O(l)
B)Cr₂O₇^2-(aq)+ 14 H⁺(aq)→ 2 Cr³⁺(aq)+ 7 H₂O(l)+ 6e^-
C)2 Cl^-(aq)→ Cl₂(aq)+ 2e^-
D)Cl₂(aq)+ 2e^- → 2 Cl^-(aq)

Question 15

What is true when the following equation is balanced in basic solution? P(s)+ PO₄^3-(aq)→ HPO₃^2-(aq)

A)H⁺ appears on the left side of the equation.
B)H⁺ appears on the right side of the equation.
C)OH^- appears on the left side of the equation.
D)OH^- appears on the right side of the equation.

Question 16

In a galvanic cell,the half-reaction MnO₄^-(aq)+ 8 H⁺(aq)+ 5 e^- → Mn²⁺(aq)+ 4 H₂O(l)is

A)an oxidation half-reaction and occurs at the anode.
B)an oxidation half-reaction and occurs at the cathode.
C)a reduction half-reaction and occurs at the anode.
D)a reduction half-reaction and occurs at the cathode.

Question 17

Based on the balanced chemical equation shown below,what volume of 0.250 M K₂S₂O_3(aq) is needed to completely react with 12.44 mL of 0.125 M KI₃(aq)? 2 S₂O₃^2-(aq)+ I₃^-(aq)→ S₄O₆^2-(aq)+ 3 I^-(aq)

A)3.11 mL
B)6.22 mL
C)12.4 mL
D)49.8 mL

Question 18

Determine the number of water molecules necessary to balance the reduction half reaction of that occurs in a basic solution.

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

Question 19

According to the balanced chemical equation 5 H₂C₂O₄(aq)+ 2 MnO₄^-(aq)+ 6 H⁺(aq)→ 10 CO₂(g)+ 2 Mn²⁺(aq)+ 8 H₂O(l)
0.3500 grams of oxalic acid,H₂C₂O₄ will react with ________ mL of 0.100 M potassium permanganate,KMnO₄ solution.

A)15.5 mL
B)38.9 mL
C)77.7 mL
D)97.2 mL

Question 20

Which cell involves a nonspontaneous redox reaction?

A)concentration cell
B)electrolytic cell
C)fuel cell
D)galvanic cell

Question 21

What is the balanced chemical equation for the galvanic cell reaction expressed using shorthand notation below? Al(s)∣ Al³⁺(aq)∣∣ Ni²⁺(aq)∣ Ni(s)

A)2 Al(s)+ 3 Ni²⁺(aq)→ 2 Al³⁺(aq)+ 3 Ni(s)
B)3 Al(s)+ 2 Ni²⁺(aq)→ 3 Al³⁺(aq)+ 2 Ni(s)
C)2 Ni(s)+ 3 Al³⁺(aq)→ 2 Ni²⁺(aq)+ 3 Al(s)
D)3 Ni(s)+ 2 Al³⁺(aq)→ 3 Ni²⁺(aq)+ 2 Al(s)

Question 22

The nickel-cadmium battery cell has a standard potential of +1.20 V.The cell reaction is 2 NiO(OH)(s)+ Cd(s)+ 2 H₂O(l)→ 2 Ni(OH)₂(s)+ Cd(OH)₂(s).
What is the standard free energy change for this reaction?

A)-38.7 kJ
B)-116 kJ
C)-232 kJ
D)-463 kJ

Question 23

For the hypothetical reaction A + B^x → A^x + B,E° = 1.19 V = and ΔG° = -115 kJ.For this reaction the value of x = .

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

Question 24

Which is not true for standard electrode potentials?

A)Cell constituents are in their standard states.
B)E° for oxidation is the negative of E° for reduction.
C)The half-reactions are written as reductions.
D)The potential for the standard hydrogen electrode is chosen to be +1.00 V.

Question 25

What is the shorthand notation that represents the following galvanic cell reaction? 2 Fe²⁺(aq)+ Cl₂(g)→ 2 Fe³⁺(aq)+ 2 Cl^-(aq)

A)Fe²⁺(aq)∣ Fe³⁺(aq)∣∣ Cl₂(g)∣ Cl^-(aq)
B)Fe(s)∣ Fe²⁺(aq)∣∣ Fe³⁺(aq)Cl₂(g)∣ Cl^-(aq)∣ C(s)
C)Pt(s)∣ Fe³⁺(aq),Fe²⁺(aq),Cl₂(g)∣∣ Cl^-(aq)∣ C(s)
D)Pt(s)∣ Fe²⁺(aq),Fe³⁺(aq)∣∣ Cl₂(g)∣ Cl^-(aq)∣ C(s)

Question 26

What is the shorthand notation that represents the following galvanic cell reaction? Fe(s)+ Cu(NO₃)₂(aq)→ Fe(NO₃)₂(aq)+ Cu(s)

A)Fe(s)∣ Fe²⁺(aq)∣∣ Cu²⁺(aq)∣ Cu(s)
B)Cu(s)∣ Cu²⁺(aq)∣∣ Fe²⁺(aq)∣ Fe(s)
C)Fe(s)∣ NO₃^-(aq)∣∣ NO₃^-(aq)∣ Cu(s)
D)Cu(s)∣ Cu(NO₃)₂(aq)∣∣ Fe(NO₃)₂(aq)∣ Fe(s)

Question 27

The cell reaction for a dry cell battery is Zn(s)+ 2 MnO₂(s)+ 2 NH₄⁺(aq)→ 2 NH₃(aq)+ Mn₂O₃(s)+ Zn²⁺(aq)+ H₂O(l).
The standard cell potential for this cell is 1.56 V.What is the standard free energy change for this cell?

A)+151 kJ
B)-151 kJ
C)-301 kJ
D)-602 kJ

Question 28

The shorthand notation for the galvanic cell reaction Fe³⁺(aq)+ 2 I^-(aq)→ Fe²⁺(aq)+ I₂(s)requires an inert electrode on

A)both sides of the salt bridge.
B)neither side of the salt bridge.
C)only on the left side of the salt bridge.
D)only on the right side of the salt bridge.

Question 29

Write the overall cell reaction for the galvanic cell given below. Pt(s)∣ H₂(g)∣ H⁺(aq)∣∣ Cl₂(g)∣ Cl^-(aq)∣ Pt(s)

A)Pt(s)+ H₂(g)+ Cl^-(aq)→ Pt(s)+ 2 H⁺(aq)+ 2 Cl₂(g)
B)2 H⁺(aq)+ 2 Cl₂(g)→ 2 HCl(aq)
C)H₂(g)+ Cl₂(g)→ 2 H⁺(aq)+ 2 Cl^-(aq)
D)No reaction would occur because there is no salt bridge.

Question 30

What is the reduction half-reaction for the following overall cell reaction? Ni²⁺(aq)+ 2 Ag(s)→ Ni(s)+ 2 Ag⁺(aq)

A)Ag(s)+ e^- → Ag⁺(aq)
B)Ag⁺(aq)+ e^- → Ag(s)
C)Ni²⁺(aq)+ 2 e^- → Ni(s)
D)Ni²⁺(aq)+ e^- → Ni(s)

Question 31

What is the balanced equation for the galvanic cell reaction expressed using shorthand notation below? Mg(s)∣ Mg²⁺(aq)∣∣ Cl₂(g)∣ Cl^-(aq)∣ C(s)

A)Mg(s)+ 2 Cl^-(aq)→ Mg²⁺(aq)+ Cl₂(g)
B)Mg(s)+ Cl₂(g)→ Mg²⁺(aq)+ 2 Cl^-(aq)
C)Mg²⁺(aq)+ 2 Cl^-(aq)→ Mg(s)+ Cl₂(g)
D)Mg²⁺(aq)+ 2 Cl^-(aq)→ MgCl₂(s)

Question 32

For the reaction 2 Al(s)+ 3 Co²⁺(aq)→ 2 Al³⁺(aq)+ 3 Co(s),ΔG° is -799 kJ.What is E° for a standard cell based on this reaction?

A)+1.38 V
B)+2.76 V
C)+4.14 V
D)+8.28 V

Question 33

What is the shorthand notation for a galvanic cell that represents the following galvanic cell reaction? Br₂(l)+ 2 I^-(aq)→ 2 Br^-(aq)+ I₂(s)

A)I^-(aq)|I₂(s)∣∣Br₂(l)|Br^-(aq)
B)I^-(aq)|I₂(s)∣∣Br₂(l)|Br^-(aq)|Pt(s)
C)Pt(s)|I^-(aq)|I₂(s)∣∣Br₂(l)|Br^-(aq)
D)Pt(s)|I^-(aq)|I₂(s)∣∣Br₂(l)|Br^-(aq)}Pt(s)

Question 34

For the galvanic cell reaction,expressed below using shorthand notation,what half-reaction occurs at the cathode? Zn(s)∣ Zn²⁺(aq)∣∣ Ni²⁺(aq)∣ Ni(s)

A)Zn(s)→ Zn²⁺(aq)+ 2 e^-
B)Zn²⁺(aq)+ 2 e^- → Zn(s)
C)Ni(s)→ Ni²⁺(aq)+ 2 e^-
D)Ni²⁺(aq)+ 2 e^- → Ni(s)

Question 35

The iron content of foods can be determined by dissolving them in acid (forming Fe³⁺),reducing the iron(III)to iron(II),and titrating with cerium(IV): Fe²⁺(aq)+ Ce⁴⁺(aq)→ Fe³⁺(aq)+ Ce³⁺(aq).
Identify the two half-reactions in the above reaction.

A)oxidation half-reaction reduction half-reaction
Fe²⁺(aq)+ e^-→ Fe³⁺(aq)Ce⁴⁺(aq)→ Ce³⁺(aq)+ e^-
B)oxidation half-reaction reduction half-reaction
Fe²⁺(aq)→ Fe³⁺(aq)+ e^- Ce⁴⁺(aq)+ e^- → Ce³⁺(aq)
C)oxidation half-reaction reduction half-reaction
Ce⁴⁺(aq)+ e^- → Ce³⁺(aq)Fe²⁺(aq)→ Fe³⁺(aq)+ e^-
D)oxidation half-reaction reduction half-reaction
Ce⁴⁺(aq)→ Ce³⁺(aq)+ e^- Fe²⁺(aq)+ e^- → Fe³⁺(aq)

Question 36

Doubling all the coefficients in the equation for the cell reaction

A)doubles both E° and ΔG°.
B)doubles E°,but does not change ΔG°.
C)doubles ΔG°,but does not change E°.
D)does not change E° or ΔG°.

Question 37

For a galvanic cell that uses the following two half-reactions, Cr₂O₇^2-(aq)+ 14 H⁺(aq)+ 6 e^- → 2 Cr³⁺(aq)+ 7 H₂O(l)
Pb(s)→ Pb²⁺(aq)+ 2 e^-
How many moles of Pb(s)are oxidized by one mole of Cr₂O₇^2-?

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

Question 38

In a galvanic cell constructed from Pb(s)| Pb⁺²(aq)|| Hg⁺¹ | Hg(s),which of the electrodes will gain mass?

A)the anode,Pb (s)
B)the cathode,Pb (s)
C)the anode,Hg (s)
D)the cathode,Hg (s)

Question 39

What is the relation between joules (J),volts (V),and coulombs (C)?

A)1 J = 1 V × 1 C
B)1 J = 1 V ÷ 1 C
C)1 J = 1 C ÷ 1 V
D)1 J = 1 V × 1 C²

Question 40

For the hypothetical reaction A + 2 B^x → A^y + 2 B,E° = 1.50 V = and ΔG° = -305 kJ.For this reaction,if the value of x is 4,then the value of y = .

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

Question 41

Consider the galvanic cell,Pt(s)∣ H₂(1 atm)|H⁺(1 M)∣∣ Cl^-(1 M)∣ Hg₂Cl₂(s)|Hg(l).Which one of the following changes to the cell would cause the cell potential to increase (i.e. ,become more positive)?

A)decrease the mass of Pt
B)increase the mass of Pt
C)decrease the pH
D)increase the pH

Question 42

Using Table 17.1,find E° for 2 H₂O(l)→ 2 H₂(g)+ O₂(g).

A)-2.06 V
B)-1.23 V
C)-0.80 V
D)-0.40 V

Question 43

Calculate the cell potential E at 25°C for the reaction 2 Al(s)+ 3 Fe²⁺(aq)→ 2 Al³⁺(aq)+ 3 Fe(s)
Given that [Fe²⁺] = 0.020 M,[Al³⁺] = 0.10 M,and the standard reduction potential is -1.66 V for Al³⁺/Al and -0.45 V for Fe²⁺/Fe.

A)+1.03 V
B)+1.17 V
C)+1.18 V
D)+1.20 V

Question 44

What is the Al³⁺:Ag⁺concentration ratio in the cell Al(s)|Al³⁺(aq)∣∣ Ag⁺(aq)|Ag(s)if the measured cell potential is 2.34 V?

A)0.0094:1
B)0.21:1
C)4.7:1
D)110:1

Question 45

Given: Ag⁺(aq)+ e^- → Ag(s)E° = +0.799 V AgI(s)+ e^- → Ag(s)+ I^-(aq)E° = -0.152 V
Ni²⁺(aq)+ 2 e^- → Ni(s)E° = -0.267 V
Which of the following reactions should be spontaneous under standard conditions?
I.2 AgI(s)+ Ni(s)→ 2 Ag(s)+ 2 I^-(aq)+ Ni²⁺(aq)
II.Ag+(aq)+ I^-(aq)→ AgI(s)

A)I and II are both nonspontaneous.
B)I is nonspontaneous and II is spontaneous.
C)I is spontaneous and II is nonspontaneous.
D)I and II are both spontaneous.

Question 46

Based on the half-reactions and their respective standard reduction potentials below,which addition to an aqueous solution containing Fe(NO₃)₂ will result in a reaction under standard-state conditions? O₂(g)+ 4 H⁺ +4 e^- → 2 H₂O(l)1.23 V
Fe³⁺(aq)+ e^- → Fe²⁺(aq)0.77 V
Cu²⁺(aq)+ 2 e^- → Cu(s)0.34 V
2 H⁺(aq)+ 2 e^- → H₂(g)0.00 V
Ni²⁺(aq)+ + 2 e^- → Ni(s)-0.26 V
Fe²⁺(aq)+ 2 e^- → Fe(s)-0.45 V

A)aqueous copper(II)acetate
B)nickel wire
C)hydrogen gas
D)oxygen gas

Question 47

Based on the half-reactions and their respective standard reduction potentials below,what is the standard cell potential for the reaction that is expected to occur? Fe³⁺(aq)+ e^- → Fe²⁺(aq)0.77 V
Sn⁴⁺(aq)+ 2 e^- → Sn²⁺(aq)0.15 V
Pb²⁺(aq)+ 2 e^- → Pb(s)-0.13 V

A)0.28 V
B)0.64 V
C)0.90 V
D)1.03 V

Question 48

When suspected drunk drivers are tested with a Breathalyzer,the alcohol (ethanol)in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate: 3CH₃CH₂OH(aq)+ 2Cr₂O₇^-2 (aq)+ 16H⁺(aq)3CH₃CO₂H(aq)+ 4Cr⁺³(aq)+ 11H₂O (l)
If Eº for this cell is 1.30V and the standard half-cell potential of Cr₂O₇^-2(aq)to Cr⁺³ is 1.358 V,what is the standard half-cell reduction potential for the conversion of acetic acid to ethanol?

A)2.658 V
B)-2.658 V
C)+ 0.058 V
D)-0.058 V

Question 49

A galvanic cell consists of a La³⁺/La half-cell and a standard hydrogen electrode.If the La³⁺/La half-cell standard cell functions as the anode,and the standard cell potential is 2.52 V,what is the standard reduction potential for the La³⁺/La half-cell?

A)-2.52 V
B)-0.84 V
C)+0.84 V
D)+2.52 V

Question 50

Given that E° = +0.897 V,calculate E at 25°C for Pb(s)∣ Pb²⁺(0.0400 M)∣∣ Fe³⁺(0.200 M),Fe²⁺(0.0100 M)∣ Pt(s)

A)+0.779 V
B)+0.935 V
C)+1.015 V
D)+1.134 V

Question 51

The standard potential for the following galvanic cell is +0.90 V: 3 Cu²⁺(aq)+ 2 Ga(s)⇌ 3 Cu(s)+ 2 Ga³⁺(aq)
Given that the standard reduction potential for the Cu²⁺/Cu half-cell is +0.34 V,what is the standard reduction potential for the Ga³⁺/Ga half-cell?

A)-1.34 V
B)-0.56 V
C)+0.56 V
D)+1.36 V

Question 52

At 25°C,E° = +1.88 V for a cell based on the reaction 3 AgCl(s)+ Al(s)→ 3 Ag(s)+ Al³⁺(aq)+ 3 Cl^-(aq).
Find the cell potential E if [Al³⁺] = 0.20 M and [Cl^-] = 0.010 M.

A)+2.01 V
B)+2.04 V
C)+2.28 V
D)cannot be calculated without the amounts of AgCl,Al,and Ag

Question 53

Using the following standard reduction potentials Fe³⁺(aq)+ e^- → Fe²⁺(aq)E° = +0.77 V
Pb²⁺(aq)+ 2 e^- → Pb(s)E° = -0.13 V
Calculate the standard cell potential for the galvanic cell reaction given below,and determine whether or not this reaction is spontaneous under standard conditions.
Pb²⁺(aq)+ 2 Fe²⁺(aq)→ 2 Fe³⁺(aq)+ Pb(s)

A)E° = -0.90 V,nonspontaneous
B)E° = -0.90 V,spontaneous
C)E° = +0.90 V,nonspontaneous
D)E° = +0.90 V,spontaneous

Question 54

Consider the galvanic cell,Pb(s)∣ Pb²⁺(aq)∣∣ Cu²⁺(aq)∣ Cu(s).Which one of the following changes to the cell would cause the cell potential to increase (i.e. ,become more positive)?

A)increase the [Pb²⁺] concentration
B)increase the [Cu²⁺] concentration
C)increase the mass of Pb(s)
D)decrease the mass of Pb(s)

Question 55

According to Table 17.1,which will reduce water but not Mg²⁺?

A)Al³⁺(aq)
B)Al(s)
C)Na⁺(aq)
D)Na(s)

Question 56

Consider the following standard reduction potentials, Al³⁺(aq)+ 3 e^- → Al(s)E° = -1.66 V
I₂(s)+ 2 e^- → 2 I^-(aq)E° = +0.54 V
Under standard conditions,

A)Al³⁺(aq)is a stronger oxidizing agent than I₂(s),and I^-(aq)is a stronger reducing agent than Al(s).
B)I₂(s)is a stronger oxidizing agent than Al³⁺(aq),and Al(s)is a stronger reducing agent than I^-(aq).
C)Al(s)is a stronger oxidizing agent than I^-(aq),and Al³⁺(aq)is a stronger reducing agent than I₂(s).
D)I^-(aq)is a stronger oxidizing agent than Al(s),and I₂(s)is a stronger reducing agent than Al³⁺(aq).

Question 57

Calculate the cell potential at 25°C for the cell Fe(s)∣ (Fe²⁺(0.100 M)∣∣ Pd²⁺(1.0 × 10^-5 M)∣ Pd(s)
Given that the standard reduction potential for Fe²⁺/Fe is -0.45 V and for Pd²⁺/Pd is +0.95 V.

A)+1.16 V
B)+1.28 V
C)+1.52 V
D)+1.68 V

Question 58

Consider the following table of standard reduction potentials: Which substance is the strongest reducing agent?

A)A
B)B
C)C₃
D)C^-

Question 59

A galvanic cell consists of one half-cell that contains Ag(s)and Ag⁺(aq),and one half-cell that contains Cu(s)and Cu²⁺(aq).What species are produced at the electrodes under standard conditions? Ag⁺(aq)+ e^- → Ag(s)E° = +0.80 V
Cu²⁺(aq)+ 2 e^- → Cu(s)E° = +0.34 V

A)Ag(s)is formed at the cathode,and Cu(s)is formed at the anode.
B)Ag(s)is formed at the cathode,and Cu²⁺ (aq)is formed at the anode.
C)Cu(s)is formed at the cathode,and Ag⁺(aq)is formed at the anode.
D)Cu²⁺(aq)is formed at the cathode,and Cu(s)is formed at the anode.

Question 60

According to Table 17.1,which aqueous metal ion will reduce Ag⁺,but not Cu²⁺?

A)Fe²⁺
B)Fe³⁺
C)Mn²⁺
D)Sn²⁺

Question 61

Which statement below is not true?

A)The cell reactants in a fuel cell are continuously supplied from an external source.
B)A fuel cell is a galvanic cell.
C)Modern fuel cells can be easily regenerated using household current.
D)One of the reactants in a fuel cell is a traditional fuel.

Question 62

A cell based on the reaction below has a standard potential of +0.42 V at 25°C.If all of the species are at standard conditions except [H⁺],at what pH will the cell have a potential of zero? H₂O₂(aq)+ 2 H⁺(aq)+ 2 Cl^-(aq)→ Cl₂(aq)+ 2 H₂O(l)

A)3.55
B)7.09
C)10.6
D)14.2

Question 63

The cell reaction for a lead storage battery is: Pb(s)+ PbO₂(s)+ 2 H⁺(aq)+ 2 HSO₄^-(aq)→ 2 PbSO₄(s)+ 2 H₂O(l)
E° = +1.92 V
To provide a potential of about 12 V,one could

A)adjust the pH to 12.
B)adjust the pH to 1.
C)connect six cells in series.
D)greatly increase the surface area of the Pb(s)and PbO₂(s).

Question 64

Which of the following reactions is most suitable for a fuel cell?

A)MnO₂(s)+ Li(s)→ LiMnO₂(s)
B)Pb(s)+ PbO₂(s)+ 2 H⁺(aq)+ HSO₄^-(aq)→ PbSO₄(s)+ 2 H₂O(l)
C)HgO(l)+ Zn(s)→ ZnO(s)+ Hg(l)
D)2 CO(g)+ O₂(g)→ 2 CO₂(g)

Question 65

Ag⁺(aq)+ e^- → Ag(s)E° = +0.800 V AgBr(s)+ e^- → Ag(s)+ Br^-(aq)E° = +0.071 V
Br₂(l)+ 2 e^- → 2 Br^-(aq)E° = +1.066 V
Use some of the data above to calculate K_sp at 25°C for AgBr.

A)6.3 × 10^-2
B)4.9 × 10^-13
C)1.9 × 10^-15
D)12.4× 10^-34

Question 66

Which is most often used in the laboratory to measure pH?

A)a standard hydrogen electrode
B)a glass electrode
C)a Daniell cell
D)a conductivity cell

Question 67

Which of the following statements concerning a lithium battery is false?

A)A lithium battery is rechargeable.
B)A lithium battery has a relatively high voltage,due in part to the high oxidation potential of lithium.
C)It takes a small mass of lithium to provide one mole of electrons in the cell reaction.
D)The cell reaction produces toxic mercury,so the batteries should be recycled.

Question 68

How many moles of electrons,n,are transferred in the following reduction-oxidation reaction? 2 MnO₄^-(aq)+ 16 H⁺(aq)+ 10 Cl^-(aq)→ 2 Mn²⁺(aq)+ 5 Cl₂(g)+ 8 H₂O(l)

A)2
B)4
C)5
D)10

Question 69

The equilibrium constant,K,can be calculated from

A)E°.
B)E.
C)either E° or E.
D)neither E° nor E.

Question 70

Consider the following cell: Pt(s)∣ H₂(g,p₁)∣ H⁺(aq,pH_A)∣∣ H⁺(aq,pH_C)∣ H₂(g,p₂)∣ Pt(s)
Where pH_A is the pH of the aqueous solution in the anode half-cell and pH_C is the pH of the aqueous solution in the cathode half-cell.If the partial pressure of H₂(g)is the same for both half-cells, (p₁ = p₂),then E for the cell at 25°C is

A)0.0296 V log (pH_A/pH_C).
B)0.0296 V log (pH_C/pH_A).
C)0.0592 V (pH_A - pH_C).
D)0.0592 V (pH_C - pH_A).

Question 71

Given that E°_red = -0.26 V for Ni²⁺/Ni at 25°C,find E° and E for the concentration cell expressed using shorthand notation below. Ni(s)∣ Ni²⁺(aq,1.0 × 10^-5 M)∣∣ Ni²⁺(aq,0.100 M)∣ Ni(s)

A)E° = 0.00 V and E = +0.24 V
B)E° = 0.00 V and E = +0.12 V
C)E° = -0.26 V and E = -0.02 V
D)E° = -0.26 V and E = -0.14 V

Question 72

If the cell reaction involves ions in solution,as the cell reaction in a galvanic cell continues,

A)E for the cell increases.
B)E for the cell decreases.
C)E° for the cell increases.
D)E° for the cell decreases.

Question 73

Consider the half-reaction: MnO₄^-(aq)+ 8 H⁺(aq)+ 5 e- → Mn²⁺(aq)+ 4 H₂O(l).The formation of MnO₄^- from Mn²⁺ occurs most readily when the solution is

A)acidic.
B)neutral.
C)basic.
D)The reaction is not dependent upon pH.

Question 74

For a particular battery based on one of the following reactions,E is expected to remain constant with time until the cell reactants are almost completely consumed.Which is the appropriate reaction?

A)Zn(s)+ 2 MnO₂(s)+ 2 NH₄⁺(aq)→ 2 NH₃(aq)+ Mn₂O₃(s)+ Zn²⁺(aq)+ H₂O(l)
B)2 NiO(OH)(s)+ Cd(s)+ 2 H₂O(l)→ 2 Ni(OH)₂(s)+ Cd(OH)₂(s)
C)Pb(s)+ PbO₂(s)+ 2 H⁺(aq)+ 2 HSO₄^-(aq)→ 2 PbSO₄(s)+ 2 H₂O(l)
D)Zn(s)+ Cu²⁺(aq)→ Zn²⁺(aq)+ Cu(s)

Question 75

When a cell reaction reaches equilibrium,

A)E° = 0.
B)E = 0.
C)both E° and E = 0.
D)neither E° nor E = 0.

Question 76

For a particular cell based on the reaction: 3 AgCl(s)+ Al(s)→ 3 Ag(s)+ Al³⁺(aq)+ 3 Cl^-(aq)
E = +1.750 V and E° = +1.884 V at 25°C.
What is the value of the equilibrium constant,K,at 25°C for the reaction?

A)3.6 × 10²⁹
B)6.7 × 10³¹
C)4.8 × 10⁸⁸
D)3.0 × 10⁹⁵

Question 77

The following cell has a potential of 0.45 V at 25°C. Pt(s)∣ H₂(1 atm)|H⁺(? M)∣∣ Cl^-(1 M)∣ Hg₂Cl₂(s)|Hg(l)
The standard half-cell potential for the half-reaction Hg₂Cl₂(s)+ 2 e^- → 2 Hg(l)+ 2 Cl^-(aq)is 0.28 V.What is the pH in the anode compartment?

A)2.9
B)4.7
C)7.6
D)12.3

Question 78

Shown below are the reactions occurring in the direct methanol fuel cell (DMFC). I.2 CH₃OH(aq)+ 2 H₂O(l)→ 2 CO₂(g)+12 H⁺(aq)+12 e^-
II.3 O₂(g)+ 12 H⁺(aq)+ 12 e^- → 6 H₂O(l)
Overall 2 CH₃OH(aq)+ 3 O₂(g)→ 2 CO₂(g)+ 4 H₂O(l)
Which is the anode reaction,and what is being oxidized in the overall reaction?

A)I,CH₃OH
B)I,H₂O
C)II,O₂
D)II,H⁺

Question 79

Given and calculate E at 25°C for a cell based on the reaction:

A)-0.09 V
B)+0.12 V
C)+0.15 V
D)+0.30 V

Question 80

When suspected drunk drivers are tested with a Breathalyzer,the alcohol (ethanol)in the exhaled breath is oxidized to acetic acid with an acidic solution of potassium dichromate: 3 CH₃CH₂OH(aq)+ 2 Cr₂O₇^-2 (aq)+ 16 H⁺(aq)3CH₃CO₂H(aq)+ 4Cr⁺³(aq)+ 11H₂O (l)
What is the value of E for the reaction when the concentrations of ethanol,acetic acid,Cr₂O₇^-2,and Cr⁺³,are 1.0M and the pH is 4.00? (Eº for this cell is 1.30V and the temperature is 298K).
Equations to solve this problem are below.
Ε = ε° - lnQ
Ε = 1.30 - ln

A)1.62 V
B)1.30 V
C)0.98 V
D)1.24 V