Chemistry for Changing Times, 14e (Hill/McCreary)
Chapter 8 Oxidation and Reduction
8.1 Multiple Choice Questions
1) With respect to energy content, reduced forms of matter are generally
A) low in potential energy and often make good fuels.
B) high in potential energy and often make good fuels.
C) low in potential energy and are poor fuels.
D) high in potential energy and are poor fuels.
2) Which of the following is a definition of reduction?
A) Reduction is the gain of oxygen.
B) Reduction is the gain of hydrogen.
C) Reduction is the loss of hydrogen.
D) Reduction is the gain of BOTH electrons AND oxygen.
3) The oxidation number of F-1 is
A) –1.
B) 0.
C) +1.
D) 2.
4) When C3H8 is burned in oxygen, the products are
A) C + H2.
B) CH2 + H2O.
C) CO2 + H2.
D) CO2 + H2O.
5) In which of the following is the reactant undergoing oxidation? (Note: These reactions are not complete
chemical equations.)
A) Cl2 → 2 Cl–
B) WO3 → W
C) 2 H+ → H2
D) C → CO2
6) The carbon in C2H6O2 is ________ in the following reaction: C2H6O2 → C2H4O2 + H2
A) oxidized
B) reduced
C) neutralized
D) electrolyzed
7) In which of the following is the reactant undergoing reduction? (Note: These reactions are not
complete chemical equations.)
A) C2H4O → C2H4O2
B) C2H4O → C2H6O
C) CO → CO2
D) CH4 → C
8) In which of the following partial reactions is the reactant undergoing reduction? (Note: The reactions
are not complete.)
A) PbO → Pb
B) KClO2 → KClO3
C) SnO → SnO2
D) Cu2O → CuO
9) Consider the following unbalanced equation between copper(I) ions and iron to produce copper metal
and iron(II) ions: Cu+ + Fe → Cu + Fe2+ What is oxidized in this reaction?
A) copper(I) ion
B) iron
C) copper
D) iron(II) ion
10) Every reduction reaction MUST be accompanied by
A) an oxidation reaction.
B) formation of ionic bonds.
C) formation of triple bonds.
D) formation of oxygen.
11) All redox reactions occur with the transfer of
A) protons.
B) electrons.
C) chlorine.
D) nitrogen.
12) The black, granular material that fills a dry cell in a common flashlight (between the carbon rod and
the zinc shell) is manganese(II) oxide, MnO2. The oxidation number of manganese in MnO2 is
A) +2.
B) –2.
C) +4.
D) –4.
13) Which of the following is a definition of oxidation?
A) Oxidation is the loss of electrons.
B) Oxidation is the addition of hydrogen.
C) Oxidation is the loss of oxygen.
D) Oxidation is the addition of electrons.
14) The oxidation number for l in l2 is
A) –2.
B) –1.
C) 0.
D) +1.
15) What is reduced in the following reaction?
2 Bi3+ + 3 Mg → 2 Bi + 3 Mg2+
A) Bi3+
B) Mg
C) Bi
D) Mg2+
16) What is the oxidation number of bismuth in Bi2O3?
A) +1
B) +2
C) +3
D) +6
17) Consider the following unbalanced half-reaction: MnO4– → MnO2. The oxidation number of Mn
changes from ________, and the Mn is ________.
A) +4 to +7; reduced
B) +7 to +4; oxidized
C) +4 to +7; oxidized
D) +7 to +4; reduced
18) Sodium bisulfite converts bromine (Br2) to bromide (Br–). Sodium bisulfite is a(n)
A) acid.
B) base.
C) oxidizing agent.
D) reducing agent.
19) In the reaction Cu+ + Fe → Cu + Fe2+ (Note: The reaction is not balanced.)
A) Fe is the reducing agent.
B) Cu is the reducing agent.
C) Cu+ is the reducing agent.
D) Fe2+ is the reducing agent.
20) Which substance is an oxidizing agent?
A) NaOH
B) H2O2
C) HI
D) LiBr
21) Hydrogen gas converts tungsten oxide to tungsten metal. Hydrogen (H2) is a(n)
A) acid.
B) base.
C) oxidizing agent.
D) reducing agent.
22) Which substance is a reducing agent?
A) C
B) I2
C) H2O2
D) TeO2
23) In a reaction, the substance undergoing reduction serves as the
A) electron donor.
B) proton donor.
C) oxidizing agent.
D) reducing agent.
24) In the following reaction, hydrogen is the ________.
CuO + H2 → Cu + H2O
A) electron donor
B) proton donor
C) oxidizing agent
D) reducing agent
25) In the reaction Fe2O3 + 3 H2 → 2 Fe + 3 H2O, the reducing agent is
A) Fe2O3.
B) H2.
C) Fe.
D) H2O.
26) Copper is plated on zinc by immersing a piece of zinc into a solution containing copper(II) ions. In
the plating reaction, copper II ions
A) gain two electrons and is are oxidized.
B) gain two electrons and is are reduced.
C) lose two electrons and is are reduced.
D) lose two electrons and is are oxidized.
27) Copper is plated on zinc by immersing a piece of zinc into a solution containing copper(II) ions. In
the plating reaction, copper(II) ions
A) lose two electrons and are oxidized.
B) lose two electrons and are reduced.
C) gain two electrons and are oxidized.
D) gain two electrons and are reduced.
28) Silver is plated on copper by immersing a piece of copper into a solution containing silver ions. In the
plating reaction, silver ions
A) lose one electron and are oxidized.
B) lose one electron and are reduced.
C) gain one electron and are oxidized.
D) gain one electron and are reduced.
29) Silver is plated on copper by immersing a piece of copper into a solution containing silver ions. In the
plating reaction, copper
A) is oxidized and is the oxidizing agent.
B) is oxidized and is the reducing agent.
C) is reduced and is the oxidizing agent.
D) is reduced and is the reducing agent.
30) Silver is plated on copper by immersing a piece of copper into a solution containing silver ions. In the
plating reaction, silver ions
A) are oxidized and are the oxidizing agent.
B) are oxidized and are the reducing agent.
C) are reduced and are the oxidizing agent.
D) are reduced and are the reducing agent.
31) An electrochemical cell is a device that converts chemical energy into
A) electrical energy.
B) chemical energy.
C) nuclear energy.
D) light energy.
32) A device that generates an electrical current by taking advantage of a difference in the spontaneous
tendency of substances to lose and gain electrons is called an
A) electrochemical cell.
B) electrolysis cell.
C) electroplating cell.
D) electrolyte cell.
33) A battery is a device that converts chemical energy into
A) electrical energy.
B) chemical energy.
C) nuclear energy.
D) light energy.
34) A major advantage of lead storage batteries is that they are
A) lightweight.
B) rechargeable.
C) disposable.
D) all of the above
35) The small “button” cells used in hearing aids and hand calculators are being replaced by ________
cells.
A) Ni-Cad
B) hydrogen
C) zinc-air
D) copper-acid
36) A substance that is produced as a lead-acid storage battery generates an electric current is
A) Pb.
B) PbSO4.
C) PbO2.
D) H2SO4.
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37) A substance that is reduced as a lead-acid storage battery generates an electric current is
A) Pb.
B) PbSO4.
C) PbO2.
D) H2SO4.
38) Which of the following statements is true for electrochemical cells?
A) Oxidation occurs at the anode.
B) Oxidation occurs at the cathode.
C) Reduction occurs at the anode.
D) Both oxidation and reduction occur at the cathode.
39) Consider the following reaction: 2 Fe + 3 Mg2+ → 2 Fe3+ + 3 Mg
The half-reaction for the oxidation in this reaction is
A) Fe → Fe3+ + 3 e–
B) Fe3+ + 3 e– → Fe
C) Mg → Mg2+ + 2 e–
D) Mg2+ + 2 e– → Mg
40) Consider the following reaction: 2 Fe + 3 Mg2+ → 2 Fe3+ + 3 Mg
The half-reaction for the reduction in this reaction is
A) Fe → Fe3+ + 3 e–
B) Fe3+ + 3 e– → Fe
C) Mg → Mg2+ + 2 e–
D) Mg2+ + 2 e– → Mg
41) A battery in which a fuel is oxidized at the anode and oxygen is reduced at the cathode is a(n)
A) alkaline battery.
B) fuel cell.
C) lead storage battery.
D) lithium battery.
42) Photochromic lenses contain
A) only AgCl embedded in the glass.
B) only CuCl embedded in the glass.
C) both AgCl and CuCl embedded in the glass.
D) neither AgCl nor CuCl embedded in the glass.
43) The corrosion of metals, such as the rusting of iron, is an example of
A) reduction.
B) oxidation.
C) proton transfer.
D) transmutation.
44) Aluminum is more reactive than iron, yet it is used today for a variety of applications in which iron
would corrode (cans, rain gutters, etc.). The reason for the corrosion durability of aluminum is that
A) aluminum does not react with oxygen.
B) very unreactive aluminum oxide forms a thin layer on aluminum.
C) aluminum does not undergo oxidation.
D) all aluminum products are treated with a plastic coating.
45) The black tarnish on silver is
A) AgOH.
B) Ag2O.
C) AgCl.
D) Ag2S.
46) The removal of silver tarnish from silverware using aluminum foil and a solution of electrolyte is an
example of
A) oxidation of aluminum metal.
B) reduction of silver ions.
C) an electrochemical cell.
D) all of the above
47) Aluminum is more reactive than iron is, but iron corrodes more quickly. This occurs because
A) aluminum is reduced in the presence of oxygen while iron is oxidized.
B) aluminum develops a coating of aluminum oxide, which protects it from further reaction.
C) iron is exposed to both oxygen and water, while aluminum is rarely exposed to water.
D) iron has a lower density than aluminum does.
48) Which of the following statements about the rusting of iron is true?
A) Iron is reduced in the presence of oxygen.
B) Iron is oxidized in the presence of oxygen.
C) The iron(III) hydroxide forms a hard coating that protects the iron from undergoing further corrosion.
D) Iron will rust more quickly in the absence of water.
49) When silver tarnishes,
A) Ag atoms are oxidized to form Ag+ ions.
B) Ag atoms are reduced to form Ag+ ions.
C) Ag+ ions are oxidized to form Ag atoms.
D) Ag+ ions are reduced to form Ag atoms.
50) Roughly ________% of all iron and steel produced each year is used to replace corroded items.
A) 4
B) 20
C) 50
D) 75
51) Most chemical explosions are ________ reactions.
A) nuclear fission
B) oxidation-reduction
C) neutralization
D) condensation
52) A mixture of ammonium nitrate (NH4NO3) and fuel oil has often been used in terrorist attacks
around the world. Which of the following statements is NOT true for this type of explosive mixture?
A) The materials are readily available to the general public.
B) It is very difficult to obtain the ammonium nitrate.
C) The ammonium nitrate serves as both an oxidizing agent and a reducing agent.
D) The reaction results in gaseous products and a huge increase in volume.
53) ANFO is an explosive mixture of ammonium nitrate, NH4NO3, and fuel oil. When this mixture
explodes, the ammonium nitrate undergoes
A) oxidation.
B) reduction.
C) both oxidation and reduction.
D) neither oxidation nor reduction.
54) ________ is used as an explosive and a heart medication.
A) Nitroglycerin
B) Trinitrotoluene
C) Ammonia nitrate
D) Urea
55) All of the following are commonly involved in explosions EXCEPT
A) aluminum metal.
B) ammonium nitrate.
C) nitroglycerin.
D) trinitrotoluene.
56) The most abundant element (by mass) in the human body is
A) oxygen.
B) carbon.
C) nitrogen.
D) water.