Oxidation Reduction Practice Exam
1. In which substance does hydrogen have an oxidation
number of zero?
A) LiH
B) H2O
C) H2S
4 HCl + MnO 2
D) H 2
2. What is the oxidation number of chromium in K 2Cr 2O7
?
A) +12
B) +2
C) +6
D) +3
3. Which polyatomic ion has a charge of 3–?
A) chromate ion
C) phosphate ion
B) oxalate ion
D) thiocyanate ion
4. What is the oxidation number of chromium in the
chromate ion, CrO 42– ?
A) +6
B) +2
C) +3
D) +8
5. During which process does an atom gain one or more
electrons?
A) transmutation
C) reduction
B) oxidation
D) neutralization
6. An oxidation-reduction reaction involves the
A)
B)
C)
D)
sharing of electrons
sharing of protons
transfer of electrons
transfer of protons
B) –1 to –2
D) +3 to +2
8. Half-reactions can be written to represent all
A)
B)
C)
D)
double-replacement reactions
neutralization reactions
fission and fusion reactions
oxidation and reduction reactions
A) Fe ®
+
2+
C) Fe ® Fe + 2e –
Fe 2+
e–
11. Which half-reaction correctly represents reduction?
A)
B)
C)
D)
B) Fe +
®
–
D) Fe + 2e ® Fe 3+
2e –
Fe 2+
Mn 4+ ® Mn 3+ + e –
Mn 4+ ® Mn 7+ + 3e –
Mn 4+ + e – ® Mn 3+
Mn 4+ + 3e – ® Mn 7+
12. Given the balanced ionic equation:
Which equation represents the oxidation half-reaction?
Zn(s) + 2e– Zn2+(aq)
Zn(s)
Zn2+(aq) + 2e–
Cu2+(aq)
Cu(s) + 2e–
Cu2+(aq) + 2e– Cu(s)
13. Given the balanced equation representing a reaction:
Fe 2O3 + 2Al
Al 2O3 + 2Fe
During this reaction, the oxidation number of Fe
changes from
A)
B)
C)
D)
9. Which equation shows conservation of charge?
MnCl 2 + 2 H2O + Cl2
A) The manganese is reduced and its oxidation
number changes from +4 to +2.
B) The manganese is oxidized and its oxidation
number changes from +4 to +2.
C) The manganese is reduced and its oxidation
number changes from +2 to +4.
D) The manganese is oxidized and its oxidation
number changes from +2 to +4.
A)
B)
C)
D)
7. Which change in oxidation number indicates oxidation?
A) –1 to +2
C) +2 to –3
10. What occurs during the reaction below?
+2 to 0 as electrons are transferred
+2 to 0 as protons are transferred
+3 to 0 as electrons are transferred
+3 to 0 as protons are transferred
14. Which equation represents an oxidation-reduction
reaction?
A)
B)
C)
D)
15. Which half-reaction for the reduction of Al 3+ to Al is
correctly balanced?
A) Al 3+ + 3e – ® Al
C) Al 3+ ® Al + 3e –
B) Al 3+ + 3e – ® 3 Al
D) Al 3+ ® 3 Al + 3e –
Oxidation Reduction Practice Exam
16. Given the unbalanced equation:
21. Based on Reference Table J, which reaction will take
place spontaneously?
_Fe + _Ag+ ® _Ag +_Fe3+
When the equation is correctly balanced using smallest
whole numbers, the coefficient of Ag+ is
A) 5
B) 2
C) 3
D) 4
17. Which metal is more active than H 2?
A) Ag
B) Au
C) Pb
D) Cu
18. Which metal reacts spontaneously with a solution
containing zinc ions?
A) copper
C) magnesium
B) nickel
D) silver
19. Which metal is more active than Ni and less active than
Zn?
A) Cu
B) Mg
C) Cr
D) Pb
20. According to Reference Table J, which reaction will
take place spontaneously?
A)
B)
C)
D)
Ni 2+ + Pb(s) ®Ni(s) + Pb2+
Au 3+ + Al(s) ® Au(s) + Al 3+
Sr 2+ + Sn(s) ®Sr(s) + Sn 2+
Fe 2+ + Cu(s) ®Fe(s) + Cu2+
A)
B)
C)
D)
Mg(s) + Ca2+(aq) ® Mg 2+(aq) + Ca(s)
Ba(s) + 2 Na + (aq) ® Ba2+(aq) + 2 Na(s)
Cl 2(g) + 2 F–(aq) ® 2 Cl –(aq) + F2(g)
I 2(g) + 2 Br–(aq) ® 2 I –(aq) + Br2(g)
22. Given the reaction:
__Cl 2(g) + __Fe2+(aq) ® __Fe 3+(aq) + __Cl–(aq)
When the equation is correctly balanced using smallest
whole numbers, the coefficient of Cl –(aq) will be
A) 1
B) 2
C) 6
D) 7
Answer Key
Oxidation Reduction
1.
D
2.
C
3.
C
4.
A
5.
C
6.
C
7.
A
8.
D
9.
C
10.
A
11.
C
12.
B
13.
C
14.
C
15.
A
16.
C
17.
C
18.
C
19.
C
20.
B
21.
B
22.
B