1. What is the oxidation number of iodine in KIO 4?
A) +1
B) –1
C) +7
9. Given the unbalanced ionic equation:
D) –7
2. Which half-reaction correctly represents reduction?
A)
B)
C)
D)
When this equation is balanced, both Fe3+ and Fe have a
coefficient of
Mn 4+ ® Mn 3+ + e –
Mn 4+ ® Mn 7+ + 3e –
Mn 4+ + e – ® Mn 3+
Mn 4+ + 3e – ® Mn 7+
3. In a redox reaction, the total number of electrons lost is
A)
B)
C)
D)
less than the total number of electrons gained
greater than the total number of electrons gained
equal to the total number of electrons gained
equal to the total number of protons gained
4. Given the electrochemical cell reaction:
Zn(s) + Ni2+ (aq) ® Zn2+ (aq) + Ni(s)
Which species is the reducing agent?
A) Zn
B) Ni 2+
C) Zn2+
D) Ni
5. When a redox reaction occurs, there must be a transfer of
A) electrons
C) protons
B) neutrons
D) ions
6. Which half-reaction correctly represents reduction?
A) Ag ® Ag+ + e –
C) Au 3+ + 3e – ® Au
B) F2 ® 2 F– + 2e –
D) Fe 2+ + e – ® Fe 3+
7. Which reaction occurs spontaneously?
A)
B)
C)
D)
Cl 2(g) + 2NaBr(aq)
Br2( ) + 2NaCl(aq)
Cl 2(g) + 2NaF(aq) F2(g) + 2NaCl(aq)
I 2(s) + 2NaBr(aq) Br 2( ) + 2NaI(aq)
I 2(s) + 2NaF(aq) F2(g) + 2NaI(aq)
8. Which metal is more active than Ni and less active than
Zn?
A) Cu
B) Cr
C) Mg
D) Pb
A)
B)
C)
D)
1, because a total of 6 electrons is transferred
2, because a total of 6 electrons is transferred
1, because a total of 3 electrons is transferred
2, because a total of 3 electrons is transferred
10. Given the balanced equation representing a reaction:
2Fe + 3Cu2+ ® 2Fe 3+ + 3Cu
When the iron atoms lose six moles of electrons, how
many moles of electrons are gained by the copper ions?
A) 12 moles
C) 3 moles
B) 2 moles
D) 6 moles
11. A voltaic cell differs from an electrolytic cell in that in
a voltaic cell
A)
B)
C)
D)
energy is produced when the reaction occurs
energy is required for the reaction to occur
both oxidation and reduction occur
neither oxidation nor reduction occurs
12. Given the balanced equation representing the reaction
occurring in a voltaic cell:
Zn(s) + Pb2 +(aq)
Zn2 + (aq) + Pb(s)
In the completed external circuit, the electrons flow
from
A)
B)
C)
D)
Pb(s) to Zn(s)
Pb2+(aq) to Zn2+(aq)
Zn(s) to Pb(s)
Zn2+(aq) to Pb 2+(aq)
13. The diagram below shows a key being plated with
copper in an electrolytic cell
Given the reduction reaction for this cell:
Cu2+(aq) + 2e-
Cu(s)
This reduction occurs at
A)
B)
C)
D)
A, which is the anode
A, which is the cathode
B, which is the anode
B, which is the cathode
Answer Key
Topic 12 - Electrochemistry
1.
C
2.
C
3.
C
4.
A
5.
A
6.
C
7.
A
8.
B
9.
B
10.
D
11.
A
12.
C
13.
B