Manarat Alriyadh International School

SCIENCES 105

Assessment
Chapter Test B
Chapter: Oxidation-Reduction Reactions
PART I In the space provided, write the letter of the term or phrase that best
completes each statement or best answers each question.
_____ 1. In the reaction 2K + Br2  2K+ + 2Br
, which species is reduced?
a. K only
b. Br2 only
c. Both K and Br2
d. Neither K nor Br2
_____ 2. Which of the following is an example of disproportionation?
a. 2H2O2  2H2O + O2
b. 2H2O  H3O+ + OH

c. Cu + 2AgNO3  Cu(NO3)2 + 2Ag
d. 2Li + 2H2O  2LiOH + H2
_____ 3. In the silver half-reaction Ag2 + + 2e
Ag(s), silver ions change into
silver solid because they are
a. oxidized.
b. reduced.
c. ionized.
d. disintegrated.
_____ 4. In the oxidation-reduction reaction H2O + 2MnO2 + Zn 
Mn2O3 + Zn(OH)2, the half-reaction of the zinc is
a. Zn(OH)2  Zn + 2e
.
b. Zn(OH)2  Zn + 2OH
.
c. Zn + 2OH
 Zn(OH)2 + 2e
.
d. Zn + 2OH
+ 2e
 Zn(OH)2.
_____ 5. Consider the two half-reactions below.
I.Pb + HSO4
 PbSO4
II.PbO2 + HSO4
 PbSO4 + 2H2O
_____ The reactant lead, Pb, is
a. oxidized in both.
b. reduced in both.
c. disproportionated in both.
d. oxidized in I and reduced in II.
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Modern Chemistry 3 Chapter Test
Chapter Test B, continued
_____ 6. In the reaction Zn + CuSO4  Cu + ZnSO4,
a. Cu is oxidized and Zn2 + is reduced.
b. Cu is reduced and Zn2 + is oxidized.
c. Cu2 + is oxidized and Zn is reduced.
d. Cu2 + is reduced and Zn is oxidized.
_____ 7. During redox reactions, reducing agents
a. attain a more negative oxidation state.
b. attain a more positive oxidation state.
c. keep the same oxidation state.
d. are not present.
_____ 8. The stronger oxidizing agent of two elements will usually be
a. oxidized.
b. reduced.
c. absorbed.
d. disproportionated.
_____ 9. In a reduction reaction, the oxidation number becomes more negative
due to
a. loss of electrons.
b. gain of electrons.
c. disproportionation.
d. addition of OH
ions.
_____ 10. When a metal is separated from oxygen, the reaction leaves a much
smaller amount of pure metal. The impure metal is said to have been
a. reduced.
b. oxidized.
c. deoxygenated.
d. ionized.