Electrochemistry Multiple Choice

January 1999

37. Consider the following redox reaction:

2MnO4- + 3ClO3- + H2O  3ClO4- + 2MnO2 + 2OH-

The reducing agent is

A. H2O

B. ClO3-

C. MnO2

D. MnO4-

38. Consider the following reaction that occurs in a breathalyzer:

2Cr2O72-(aq) + 16H+(aq) + 3C2H5OH(g)  4Cr3+(aq) + 11H2O(l) + 3CH3COOH(aq)

Which atom undergoes an increase in oxidation number?

A. carbon

B. oxygen

C. hydrogen

D. chromium

39. Which of the following is the strongest reducing agent?

A. Al

B. Cu

C. Zn

D. Mg

40. Which of the following reactions is spontaneous at standard conditions?

A. Pb + Cu2+ Cu + Pb 2+

B. H2 + Mg2+ Mg + 2H+

C. Br2 + 2Cl- Cl2 + 2Br-

D. 2Ag + Cu2+ Cu + 2Ag+

41. Consider the following redox reaction:

3ClO2- 2ClO3- + Cl- (basic)

The reduction half-reaction that occurs is

A. ClO2- + 2H2O + 4e- Cl- + 4OH-

B. ClO2- + 2H2O  Cl- + 4OH- + 4e-

C. ClO2- + 2OH- + 2e- ClO3- + H2O

D. ClO2- + 2OH-  ClO3- + H2O + 2e-

42. Vanadium metal, V, reacts spontaneously with Cd2, but not with Ti2. Based on these results, the order of oxidizing agents, from strongest to weakest, is

A. Cd2+, V2+, Ti2+

B. V2+, Ti2+ , Cd2+

C. Ti2+, Cd2+, V2+

D. Ti2+, V2+, Cd2+

43. Consider the following electrochemical cell:

In this operating electrochemical cell,

A. electrons flow toward the Cu and the Cu2ions migrate toward the Zn.

B. electrons flow toward the Cu and the Zn2ions migrate toward the Cu.

C. electrons flow toward the Zn and the Cu2ions migrate toward the Zn.

D. electrons flow toward the Zn and the Zn2ions migrate toward the Cu.

44. Which of the following affects the potentials of electrochemical cells?

A. I and II only.

B. II and III only.

C. I and III only.

D. I, II and III.

45. In the rusting of iron, the reduction reaction that occurs is

A. Fe  Fe2+ + 2e-

B. Fe2+ + 2e- Fe

C. 2H2O  O2 + 4H+ + 4e-

D. O2 + 2H2O + 4e- 4OH-

46. During a cathodic protection, the sacrificial anode

A. accepts electrons from the protected metal.

B. reacts spontaneously with the protected metal.

C. oxidizes more readily than the protected metal.

D. causes the protected metal to become an anode.

47. During the electrolysis of an aqueous solution of KI, what substance is formed at the cathode?

A. iodine

B. oxygen

C. hydrogen

D. potassium

48. When electroplating an iron medallion with nickel,

A. the medallion is an anode.

B. the cathode is pure nickel.

C. the solution contains Ni2.

D. the anode reaction is Ni22eNi

April 1999

37. Which of the following represents the formation of a stronger acid as a result of oxidation?

A. H2SO3  H2S

B. HClO4 HCl

C. H2SO3 H2SO4

D. HCO3- H2CO3

38. Chlorine has an oxidation number of 5 in

A. NaClO

B. NaClO2

C. NaClO3

D. NaClO4

39. Consider the following:

NO2 N2O3

The nitrogen atom in each NO2

A. loses one electron.

B. gains one electron.

C. loses two electrons.

D. gains two electrons.

40. Which of the following is the strongest oxidizing agent?

A. BrO3-C. S2O82-

B. ClO4-D. Cr2O72-

41. Consider the following half-reaction:

1 AsH3 + __ H2O  __ H3AsO3 + ? H+ + __e-

When this half-reaction equation is balanced, the coefficient for His

A. 2

B. 3

C. 6

D. 9

42. When a strip of zinc is placed in a 1.0M copper (II) chloride solution,

A. no change occurs.

B. the [Clincreases.

C. the [Cu2increases.

D. the [Zn2increases.

43. Consider the following electrochemical cell:

What changes occur when the cell is in operation?

44. A redox titration is performed in order to determine the [H2O2].

Which of the following would not be a suitable reagent to use?

A. acidified IO3-

B. acidified SO42-

C. acidified MnO4-

D. acidified Cr2O72-

45. Ethanol, C2H5OH, is oxidized by an acidified dichromate solution according to the following equation:

2Cr2O72-+ 16H++ 3C2H5OH  4Cr3++ 11H2O + 3CH3COOH

The Efor the reaction above is 2.98V. The Efor the oxidation of ethanol is

A. 0.52V

B. 1.23V

C. 1.75V

D. 2.98V

46. Which of the following must be present to produce rust by the corrosion of iron?

A. I only

B. II only

C. I and II only

D. I, II and III

47. Why can an object not be plated with magnesium using 1.0M MgI2?

A. Water is a stronger reducing agent than I

B. Water is a stronger oxidizing agent than I

C. Water is a stronger reducing agent than Mg2

D. Water is a stronger oxidizing agent than Mg2

48. In the electrolysis of 1.0M Na2SO4, what is formed at the cathode?

A. O2

B. H2

C. H2SO3

D. S2O82-

June 1999

37. Which of the following is capable of acting both as an oxidizing agent and a reducing agent?

A. H+

B. Na+

C. Sn2+

D. MnO4-

38. Consider the following redox reaction:

C2H12O6 + 6O2 6CO2 + 6H2O

The substance undergoing reduction is

A. O2

B. CO2

C. H2O

D. C6H12O6

39. The oxidation number of P in H4P2O7is

A. -10

B. -5

C. +5

D. +10

40. A solution containing an unknown cation reacts spontaneously with both zinc and copper. The unknown cation is

A. 1.0M H+

B. 1.0M Ag+

C. 1.0M Sr2+

D. 1.0M Mn2+

41. Which of the following half-reactions is balanced?

A. CIO- + H2O +e- Cl2 + 2OH-

B. 2CIO- + H2O +2e- Cl2 + 3OH-

C. 2CIO- + 2H2O +2e- Cl2 + 4OH-

D. 2CIO- + 2H2O Cl2 + 4OH- + 2e-

42. Which of the following is a spontaneous redox reaction?

A. Ag+ + I- AgI

B. Ag+ + Fe2+ Ag + Fe3+

C. 3Ag+ + Au  3Ag + Au3+

D. 2Ag+ + Ni2+ 2Ag + Ni

43. Salting of roads during the winter increases the corrosion of cars.

This is because the salt

A. reacts with the iron.

B. provides an electrolyte.

C. acts as a reducing agent.

D. acts as an oxidizing agent.

44. Which of the following will not react spontaneously with 1.0M HCl?

A. tin

B. lithium

C. mercury

D. aluminum

45. Consider the following electrochemical cell:

The half-reaction that occurs at the anode is

A. Ni  Ni2+ + 2e-

B. Ni2+ + 2e- Ni

C. Cu  Cu2+ + 2e-

D. Cu2+ + 2e- Cu

46. Which of the following can be produced by electrolysis from a 1.0M aqueous solution

containing its ion?

A. nickel

B. sodium

C. aluminum

D. magnesium

47. In the electrolysis of molten ZnCl2using carbon electrodes, the reaction that occurs

at the anode is

A. Zn  Zn2+ + 2e-

B. Zn 2+ + 2e- Zn

C. 2Cl- Cl2 + 2e-

D. Cl2 + 2e- 2Cl-

48. In order for an electrolytic cell to operate, it must have

A. a voltmeter.

B. a salt bridge.

C. a power supply.

D. an aqueous solution.

August 1999

38. The following reaction represents the process used to produce iron from iron (III) oxide:

Fe2O3 + 3CO  2Fe + 3CO2

What is the reducing agent in this process?

A. Fe

B. CO

C. CO2

D. Fe2O3

39. Consider the following reaction:

2HNO2 + 2I- + 2H+ 2NO + I2 + 2H2O

The oxidation number for each nitrogen atom

A. increases by 1

B. increases by 2

C. decreases by 1

D. decreases by 2

40. Which of the following reactions is spontaneous?

A. 2I- + Ag  Ag+ + I2

B. Co2+ + Cu  Co + Cu2+

C. Cu2+ + Pb  Pb2+ + Cu

D. Ni2+ + 2Ag  2Ag+ + Ni

41. Consider the following redox reaction for a lead-acid storage cell:

Pb + PbO2 + 4H+ + 2SO42- 2PbSO4 + 2H2O

The balanced, reduction half-reaction is

A. Pb + SO42- PbSO4 + 2e-

B. Pb + 2H+ + SO42- PbSO4 + H2O + 2e-

C. PbO2 + 4H+ + SO42- + 2e- PbSO4 + 2H2O

D. PbO2 + SO42- + 4H2O + 2e- PbSO4 + 4OH-

Use the following diagram to answer questions 42 and 43.

42. Which of the following statements apply to this electrochemical cell?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

43. At equilibrium, the voltage of the cell above is

A. 1.10 V

B. 0.00 V

C. 0.42 V

D. 1.10 V

44. Consider the following reaction:

Cd2+(aq) + Zn (s)  Cd(s) + Zn 2+ (aq)

The potential for the reaction is 0.36V. What is the reduction potential for the cadmium ion?

A. 1.12 V

B. 0.40 V

C. 0.40 V

D. 1.12 V

45. Which of the following involves a non-spontaneous redox reaction?

A. fuel cell

B. electroplating

C. redox titration

D. carbon dry cell

46. Consider the following redox reaction:

2MnO4- + 16H+ + 5Sn2+ 2Mn2+ + 8H2O + 5Sn4+

In a redox titration, 0.060 mol of KMnO4reacts completely with a solution of Sn(NO3)2.

How many moles of Sn(NO3)2were present in the solution?

A. 0.024 mol

B. 0.060 mol

C. 0.15 mol

D. 0.30 mol

47. What substances are formed at the anode and cathode during electrolysis of molten

sodium chloride, NaCl (l)?

48. What is the minimum voltage required to form nickel from an aqueous solution of NiI2using inert electrodes?

A. 0.26VC. 0.54V

B. 0.28VD. 0.80V

January 2000

38. Which of the following represents a redox reaction?

A. CaCO3  CaO + CO2

B. SiCl4 + 2Mg  Si + 2MgCl2

C. 2NaOH + H2SO4 2H2O + Na2SO4

D. AgBr + 2S2O32- Ag(S2O3)23- + Br-

39.Consider the following reaction:

TiCl4 + O2 TiO2 + 2Cl2

Each oxygen atom is

A. reduced and loses 2e-

B. reduced and gains 2e-

C. oxidized and loses 2e-

D. oxidized and gains 2e-

40. When NO2 acts as a reducing agent, a possible product is

A. NO

B. N2O

C. N2O4

D. N2O5

41. Which of the following 1.0M solutions will react spontaneously with lead?

A. KCl

B. CuCl2

C. ZnCl2

D. MgCl2

42. Consider the following redox reaction:

I2 + 2S2O32-  S4O62- + 2I-

In a titration, 40.00mL of Na2S2O3 is needed to react completely with 4.0 X 10-3 mol I2.

What is the concentration of Na2S2O3?

A. 0.10M

B. 0.16M

C. 0.20M

D. 0.32M

43. In an operating electrochemical cell the function of a salt bridge is to

A. allow hydrolysis to occur.

B. allow a non-spontaneous reaction to occur.

C. permit the migration of ions within the cell.

D. transfer electrons from the cathode to the anode.

Use the following diagram to answer questions 44 and 45.

44. As the cell operates, electrons flow toward

A. the Pb electrode, where Pb is oxidized.

B. the Cd electrode, where Cd is oxidized.

C. the Pb electrode, where Pb2+ is reduced.

D. the Cd electrode, where Cd2+ is reduced.

45. The E° value for the reduction of Cd2+ is

A. –0.40V

B. –0.27V

C. +0.14V

D. +0.40V

46. The following reaction occurs in an electrochemical cell:

3Cu2+ + 2Cr  2Cr3+ + 3Cu

The E° for the cell is

A. 0.40VC. 1.08V

B. 0.75VD. 2.50V

47. During the corrosion of magnesium, the anode reaction is

A. Mg  Mg2+ + 2e-

B. Mg2+ + 2e- Mg

C. 4OH- O2 + 2H2O + 4e-

D. O2 + 2H2O + 4e- 4OH-

48. A molten binary salt, ZnCl2, undergoes electrolysis. The cathode reaction is

A. Zn  Zn2+ + 2e-

B. 2Cl- Cl2 + 2e-

C. Cl2 + 2e- 2Cl-

D. Zn2+ + 2e-  Zn

April 2000

38. Manganese has an oxidation number of +4 in

A. MnO

B. MnO2

C. Mn2O3

D. Mn2O7

39. In which reaction is nitrogen reduced?

A. 2NO + O2  2NO2

B. 4NH3 + 5O2 4NO + 6H2O

C. Cu2+ + 2NO2 + 2H2O  Cu + 4H+ + 2NO3-

D. 4Zn + 10H+ + NO3- 4Zn2+ + NH4+ + 3H2O

40. An oxidizing agent will cause which of the following changes?

A. PtO2 PtO

B. PtO3 PtO2

C. Pt(OH)2 Pt

D. Pt(OH)22+ PtO3

41. Consider the overall reaction of the rechargeable nickel-cadmium battery:

NiO2(s) + Cd(s) + 2H2O(l) Ni(OH)2(s) + Cd(OH)2 (s)

Which of the following occurs at the anode as the reaction proceeds?

A. Cd loses 2e- and forms Cd(OH)2(s)

B. Cd gains 2e- and forms Cd(OH)2(s)

C. NiO2 loses 2e- and forms Ni(OH)2(s)

D. NiO2 gains 2e- and forms Ni(OH)2(s)

42. Which of the following will oxidize Fe2+?

A. I2 (s)

B. Ni (s)

C. Zn(s)

D. Br2(l)

43. Consider the following half-reaction in a basic solution:

Ag2O3 AgO (basic)

The balanced half-reaction is

A. Ag2O3 + 4H+ + 4e- AgO + 2H2O

B. Ag2O3 + 2H+ + 2e- 2AgO + H2O

C. Ag2O3 + H2O + 2e- 2AgO + 2OH-

D. Ag2O3 + 2H2O + 4e- AgO + 4OH-

44. The concentration of Fe2+ (aq) can be determined by a redox titration using

A. KBr

B. SnCl2

C. KMnO4 (basic)

D. KBrO3 (acidic)

45. Consider the following electrochemical cell:

Which of the following occurs as the cell operates?

A. Zinc electrode is reduced and increases in mass.

B. Zinc electrode is reduced and decreases in mass.

C. Zinc electrode is oxidized and increases in mass.

D. Zinc electrode is oxidized and decreases in mass.

46. Which of the following reactants would produce an E° of +0.63V?

A. Ag+ + I2

B. Pb2+ + Zn

C. Mg2+ + Ca

D. Zn2+ + Mn

47. The process of applying an electric current through a cell to produce a chemical change is called

A. corrosion.

B. ionization.

C. hydrolysis.

D. electrolysis

48. Consider the following electrolytic cell:

The cathode reaction is

A. 2I- I2 + 2e-

B. Mg2+ + 2e- Mg

C. H2O ½O2 + 2H+ + 2e-

D. 2H2O + 2e- H2 + 2OH-

June 2000

38. A substance that is reduced during a redox reaction

A. loses mass.

B. is the anode.

C. is the reducing agent.

D. is the oxidizing agent.

39. The oxidation number of As in H4As2O7 is

A. +4

B. +5

C. +9

D. +10

40. In a reaction, the oxidation number of Cr decreases by 3. This indicates that Cr is

A. reduced.

B. oxidized.

C. neutralized.

D. a reducing agent.

41. Consider the following redox reaction:

C2H5OH + 2Cr2O72- + 16H+ 2CO2 + 4Cr3+ + 11H2O

Each carbon atom loses

A. 2 electrons

B. 4 electrons

C. 6 electrons

D. 12 electrons

42. In which of the following 1.0M solutions will both ions react spontaneously with tin?

A. Ag+ and Cu2+

B. Ni2+ and Cu2+

C. Zn2+ and Ni2+

D. Mg2+ and Zn2+

43. Consider the following half-reaction:

Bi2O4 BiO+ (acidic)

The balanced equation for this half-reaction is

A. Bi2O4 + 6H+ + 5e- BiO+ + 3H2O

B. Bi2O4 + 8H+ + 6e- 2BiO+ + 4H2O

C. Bi2O4 + 4H+ + 2e- 2BiO+ + 2H2O

D. Bi2O4 + 4H+ + 3e- 2BiO+ + 2H2O

44. To determine the concentration of Fe2+(aq)by a redox titration, we could use an acidified standard solution of

A. Sn2+

B. Pb2+

C. HCl

D. H2O2

45. Consider the following redox reactions:

2Ag+ + Cd  2Ag + Cd2+ E° = 1.20V

3Cd2+ + 2Nb  2Nb3+ + 3Cd E° =0.70V

What is the E° for Nb3+ + 3e- Nb?

A. –1.90VC. –0.50V

B. –1.10VD. –0.40V

46. Consider the overall reaction for the rechargeable nickel-cadmium battery:

Cd + NiO2 + 2H2O  Cd(OH)2 + Ni(OH)2

Which of the following occurs at the cathode as the reaction proceeds?

A. Cd loses 2e- and Cd(OH)2 forms

B. Cd gains 2e- and Cd(OH)2 forms

C. NiO2 loses 2e- and Ni(OH)2 forms

D. NiO2 gains 2e- and Ni(OH)2 forms

47. Consider the following diagram of a piece of iron, cathodically protected by magnesium:

What is happening during this process?

A. Iron acts as the anode and water is oxidized.

B. Iron acts as the cathode and oxygen is reduced.

C. Magnesium acts as the anode and iron is oxidized.

D. Magnesium acts as the cathode and iron is reduced.

48. Consider the following operating cell:

Which of the following describes the cell above?

August 2000

37. A chemical process involving the loss of electrons is a definition of

A. oxidation.

B. reduction.

C. galvanization.

D. cathodic protection.

38. Which of the following is not a redox reaction?

A. 2Mg + O2 2MgO

B. SO3 + H2SO4 H2S2O7

C. CuS + 2O2 + C  Cu + SO2 + CO2

D. 4Ag + 2H2S + O2 2Ag2S + 2H2O

39. A reducing agent will cause which of the following changes?

A. ClO3- ClO2

B. NO2- N2O4

C. H3PO3 H3PO4

D. HS2O4-  H2SO3

40. The oxidation number of zinc in a reaction increases by 2. This indicates that

A. zinc is reduced and loses 2 electrons.

B. zinc is reduced and gains 2 electrons.

C. zinc is oxidized and loses 2 electrons.

D. zinc is oxidized and gains 2 electrons.

41. Which metal will react spontaneously with water?

A. Ca

B. Ni

C. Pb

D. Hg

42. Consider the following redox reaction which occurs in a lead-acid storage cell:

PbO2(s) + Pb (s) + 2H2SO4(aq)  2PbSO4(s) + 2H2O (s)

The balanced reduction half-reaction is

A. Pb  Pb2+ + 2e-

B. Pb + SO42-  PbSO4 + 2e-

C. 2H2SO4 + 2Pb + 2e- 2PbSO4 + 2H2O

D. PbO2 + 4H+ + SO42- + 2e- PbSO4 + 2H2O

43. Consider the following redox reactions:

HClO + I- HIO + Cl- E° = +0.49V

HClO + Br- HBrO + Cl- E° = +0.15V

The relative strength of the oxidizing agents from strongest to weakest is

A. HIO > HBrO > HClO

B. HClO > HIO > HBrO

C. HBrO >HIO > HClO

D. HClO > HBrO > HIO

44. Consider the following diagram of a fuel cell in which H2 and O2 combine to produce H2O under basic conditions:

The reaction at the anode is

A. 2H+ + 2e- H2

B. ½ O2 + 2H+ + 2e- H2O

C. 4OH- O2 + 2H2O + 4e-

D. H2 + 2OH- 2H2O + 2e-

45. As the cell operates, observations include

46. What is the cell potential, E°, for this cell?

A. 0.08 V

B. 0.26 V

C. 0.60 V

D. 0.78 V

47. Consider the following electrolytic cell:

In the cell above,

A. I- migrates to the anode and gains electrons.

B. I- migrates to the cathode and loses electrons.

C. Na+ migrates to the anode and loses electrons.

D. Na+ migrates to the cathode and gains electrons.

48. Which of the following are necessary for electroplating to occur using an electrolytic cell?

A. I and II only.

B. I and III only.

C. II and III only.

D. I, II, and III.

January 2001

38. Which of the following represents a redox reaction?

A. C + O2 CO2

B. H2O + SO2 H2SO3

C. H3O+ +OH- 2H2O

D. NaCl + AgNO3 AgCl + NaNO3

39. The oxidation number of each chromium atom in Cr2O72-is

A. +5

B. +6

C. +7

D. +12

40. List the ions Co2+, Cu2+ and Zn2+ in order from strongest to weakest oxidizing agents.

A. Zn2+ > Co2+ Cu2+

B. Co2+ Cu2+ Zn2+

C. Cu2+ Zn2+ Co2+

D. Cu2+ Co2+ Zn2+

41. A piece of Cu reacts spontaneously with 1.0M Pd2+because

A. Cu is a weaker reducing agent than Pd and E° > 0.

B. Cu is a weaker reducing agent than Pd and E° < 0.

C. Cu is a stronger reducing agent than Pd and E° > 0.

D. Cu is a stronger reducing agent than Pd and E° < 0.

42. Which two species will not react spontaneously at standard conditions?

A. Co with Cl2

B. Cu with Ag+

C. Ag with Zn2+

D. Mg with Cr3+

43. When a piece of Ag is placed in 1.0M NiCl2,

A. the [Cl-] increases.

B. the [Ag+] decreases.

C. the [Ni2+] decreases.

D. no change occurs.

44. Which of the following represents the relationship between [NO3-] and the mass of the Cu electrode in the complete cell as it operates?

45. The E° for the above cell is

A. –1.10 Volts

B. –0.42 Volts

C. +0.42 Volts

D. +1.10 Volts

46. Which of the following is correct for an electrolytic cell?

47. Which of the following will inhibit the corrosion of iron?

A. high [O2(aq)]

B. wet conditions

C. coating with zinc

D. increasing the temperature

48. The products of the electrolysis of molten MgCl2using inert electrodes are

A. hydrogen and oxygen.

B. hydrogen and chlorine.

C. magnesium and oxygen.

D. magnesium and chlorine.

April 2001

38. Consider the following reaction:

Zn (s) + 2H+(aq) Zn2+(aq) + H2(g)

The species being oxidized is

A. H2

B. H+

C. Zn

D. Zn2+

39. When SO42- reacts to form S2O62-, the sulphur atoms

A. lose electrons and are reduced.

B. gain electrons and are reduced.

C. lose electrons and are oxidized.

D. gain electrons and are oxidized.

40. Which of the following is a list of metals in order from strongest to weakest reducing agents?

A. Au > Ni > Rb

B. Ni > Au > Rb

C. Ni > Rb > Au

D. Rb > Ni > Au

41. Consider the following spontaneous reaction:

Mg (s) + 2HCl (aq) MgCl2(aq) + H2(g)

Which of the following statement is correct?

A. Mg is a weaker reducing agent than H2

B. Mg is a weaker reducing agent than H+

C. Mg is a stronger reducing agent than H2

D. Mg is a stronger reducing agent than H+

42. Which of the following will not react spontaneously with H2O at standard conditions?

A. F2

B. Ca

C. Na

D. Sn

43. When a piece of Cu is placed in 1.0M AgNO3,

A. the [Ag+] increases.

B. the [Cu2+] increases.

C. the [NO3-] decreases.

D. no change occurs.

44. Which of the following diagrams represents the relationship between [Ni2+] and the mass of the Cu electrode as the cell above is in operation?

45. The E° for the above cell is

A. –0.04 volts

B. –0.60 volts

C. +0.04 volts

D. +0.60 volts

46. Which of the following describes an electrochemical cell?

47. Which of the following aqueous solutions should not be used as an electrolyte in an electrolytic cell?

A. 1.0M KOH

B. 1.0M H2SO4

C. 1.0M CuSO4

D. 1.0M C6H12O6

48. When 1.0M Na2SO4 is electrolyzed, the solution near the anode becomes

A. basic and bubbles form.

B. acidic and bubbles form.

C. basic and no bubbles form.

D. acidic and no bubbles form.

June 2001

38. Which of the following represents a redox reaction?

A. H2 + I2 2HI

B. HCl + NH3 NH4Cl

C. H2O + CO2 H2CO3

D. 2NaI + Pb(NO3)2  PbI2 + 2NaNO3

39. In an experiment, Ag+reacts spontaneously with Ru but not with Pd. The relative strength of the metals from strongest to weakest reducing agent is

A. Ag > Ru > Pd

B. Pd > Ag > Ru

C. Ru > Ag > Pd

D. Ru > Pd > Ag

40. A piece of Ag does not react spontaneously with 1.0M Ti2+ because

A. Ag+is a weaker reducing agent than Ti2+

B. Ag+is a weaker oxidizing agent than Ti2+

C. Ag+is a stronger reducing agent than Ti2+

D. Ag+is a stronger oxidizing agent than Ti2+

41. Which of the following will react spontaneously with Ag2Sat standard conditions?

A. Al

B. Au

C. Co

D. Pb

42. When a piece of Cu is placed in 1.0M HNO3,

A. the [H+]increases.

B. the [Cu2+]decreases.

C. the [NO3-] decreases.

D. no change occurs.

43. When MnO2changes to Mn2O3in an alkaline battery, manganese atoms

A. lose electrons and are reduced.

B. gain electrons and are reduced.

C. lose electrons and are oxidized.

D. gain electrons and are oxidized.

44. Which of the following diagrams represents the relationship between the mass of the

Cu electrode and the mass of the Ag electrode as the cell is in operation?

45. The E° for the above cell is

A. -1.14 Volts

B. -0.46 Volts

C. +0.46 Volts

D. +1.14 Volts

46. The value of E° for a cell can be used to determine

A. rate.

B. spontaneity.

C. temperature.

D. activation energy.

47. How is the formation of rust on an iron can inhibited by a tin coating?

A. The tin is a sacrificial anode.

B. The tin cathodically protects the iron.

C. The tin is a weaker reducing agent than iron.

D. The tin keeps the oxygen away from the iron.

48. The electrolysis of 1.0M CuF2 using inert electrodes will produce

A. copper and oxygen.

B. copper and fluorine.

C. hydrogen and oxygen.

D. hydrogen and fluorine.

August 2001

38. Consider the following spontaneous reaction:

2Al (s) + 3Cu2+(aq) 2Al3+ (aq) + 3Cu(s)

In this reaction, the oxidizing agent is

A. Al

B. Cu

C. Al3+

D. Cu2+

39. Bromine has an oxidation number of +3 in

A. KBrO

B. KBrO2

C. KBrO3

D. KBrO4

40. In an experiment, Te reacts spontaneously with Ag+but not with Ti2+. The relative strength of oxidizing agents from strongest to weakest is

A. Ag+ > Te4+ > Ti2+

B. Ag+ > Ti2+ > Te4+

C. Te4+ > Ti2+ > Ag+

D. Ti2+ > Te4+ Ag+

41. A piece of Au does not react spontaneously with 1.0M HCl. Which of the following statements is true?

A. Au is a weaker reducing agent than H2

B. Au is a stronger reducing agent than H2

C. Au is a weaker oxidizing agent than H+

D. Au is a stronger oxidizing agent than H+

42. Which two species will react spontaneously with each other at standard conditions?

A. Cl2 and Br-

B. Zn and Al3+

C. Au and Sn2+

D. I2 and SO42-

43. What occurs when a piece of Zn is placed in 1.0M Cu(NO3)2?

A. [Cu2+] decreases

B. [Zn2+] decreases

C. [NO3-]increases

D. no change occurs

44. Which of the following diagrams represents the relationship between [Zn2+]and [Ni2+] as the cell is in operation?

45. The E° for the cell in the diagram is

A. -1.02 VoltsC. +0.50 Volts

B. -0.50 VoltsD. +1.02 Volts

46. Which of the following does not affect the cell potential?

A. [Ni2+]C. temperature

B. [Zn2+]D. surface area of the electrodes

47. What type of ions move toward each electrode in an electrolytic cell?

48. The electrolysis of 1.0M NaI using inert electrodes will produce

A. sodium and iodine.C. hydrogen and iodine.

B. sodium and oxygen.D. hydrogen and oxygen.

January 2002

38. A reducing agent

A. loses electrons and is reduced.

B. gains electrons and is reduced.

C. loses electrons and is oxidized.

D. gains electrons and is oxidized.

39. Which of the following could be produced by the reduction of NO2?

A. NO

B. N2O4

C. N2O5

D. HNO3

40. Consider the following redox equation:

3NO + SO42- + Fe3+ + 2H2O → FeS + 3NO3- + 4H+

Which of the following is being oxidized?

A. NO

B. Fe3+

C. H2O

D. SO42-

41. What is the oxidation number of Cr in Cr2O72- ?

A. +6

B. +7

C. +12

D. +14

42. Which of the following represents a spontaneous redox reaction?

A. 2Br- + Hg2+ → Br2 + Hg

B. Cu + Sn4+ → Cu2+ + Sn2+

C. HCl + NaOH → NaCl + H2O

D. AuCl4- + 3Ag → Au + 4Cl- + 3Ag+

43. Which of the following is the balanced half-reaction for

N2O → NH3OH+(acidic)

A. N2O + 4H+ + 3e-→ NH3OH+

B. N2O + 3H+ + H2O → NH3OH+ + 2e-

C. N2O + 6H+ + H2O → 2NH3OH+ + 4e-

D. N2O + 6H+ + H2O + 4e- → 2NH3OH+

Use the following diagram to answer questions 44 to 46.

44. Which material could be used as the cathode to produce an E°cell = +0.46 V?

A. Pb

B. Co

C. Ag

D. MnO2

45. In what directions do the electrons and cations move?

Direction of Electrons / Direction of Cations
A. / Toward the cathode / Toward the anode
B. / Toward the cathode / Toward the cathode
C. / Toward the anode / Toward the anode
D. / Toward the anode / Toward the cathode

46. The concentration of Cu2+ in the copper half-cell will

A. increase as Cu loses electrons and is reduced.

B. increase as Cu loses electrons and is oxidized.

C. decrease as Cu gains electrons and is reduced.

D. decrease as Cu gains electrons and is oxidized.

47. Which of the following metals could be used to cathodically protect iron?

A. tin

B. lead

C. zinc

D. copper

48. Which of the following is formed at the anode during the electrolysis of 1.0M KF?

A. K

B. F2

C. H2

D. O2

April 2002

38. Which of the following describes a strong oxidizing agent?

A. a substance which loses electrons readily

B. a substance which gains electrons readily