Section 21.1
Voltaic Cells
Practice Test
1.
Which of the following is the weakest reducing agent?
a.
F
2
b.
Al
3+
c.
Al
d.
F
-
Hint
2.
A voltaic cell in which the reaction involves the combustion of one reactant with oxygen to produce electric energy is a
n
_____________.
a.
secondary battery
b.
electrolytic cell
c.
primary battery
d.
fuel cell
Hint
3.
How many moles of electrons have been transferred between the species in the following reaction? 2Cr
3+
aq
+3Cu
s
→2Cr
s
+3Cu
2+
aq
SC.B.1.4.2
a.
4
b.
3
c.
2
d.
6
Hint
4.
Under standard conditions, what is the standard cell potential for the cell? Cd
a.
Cu
2+
b.
Cu?
c.
Cu
2+
Hint
5.
Under standard conditions, which of the following is the net reaction that occurs in the cell? Cd
a.
Cu
2+
b.
Cd
2+
c.
Cu
Hint
6.
In any electrochemical cell, the cathode is the ________.
a.
electrode at which some species gains electrons
b.
electrode at which some species loses electrons
c.
positive electrode
d.
negative electrode
Hint
7.
In a voltaic cell, the salt bridge __________.
a.
is not necessary for the cell to work
b.
allows charge balance to be maintained in the cell
c.
drives electrons from one half-cell to another
d.
acts as a mechanism to allow mechanical mixing of the solutions
Hint
8.
Using a table of standard reduction potentials, which of the following is the strongest oxidizing agent?
a.
F
2
b.
F
-
c.
Al
3+
d.
Al
Hint
9.
A cell is constructed by immersing a strip of lead in a 1.0
M
Pb
NO
3
2
solution and a strip of silver in a 1.0
M
AgNO
3
solution. The circuit is completed by a wire and a salt bridge. As the cell operates, the strip of silver gains mass
only silver
, the strip of lead loses mass, and the concentration of lead ions increases in the solution around the lead strip. Which of the following represents the reaction that occurs at the cathode in this cell?
a.
Pb
2+
+ 2e
-
→ Pb
b.
Ag → Ag
+
+ e
-
c.
Pb → Pb
2+
+ 2e
-
d.
Ag
+
+ e
-
→ Ag
Hint
10.
A voltaic cell consists of a standard hydrogen electrode connected by a salt bridge and a wire to an electrode consisting of a strip of Cd metal dipping into a 1
M
solution of Cd
NO
3
2
. When the cell produces a current, the electrons flow through the wire from the _________ electrode to the ________ electrode. In this cell, the _______ electrode acts as the cathode.
SC.C.2.4.2
a.
Cd, H
2
, H
2
b.
Cd, H
2
, Cd
c.
H
2
, Cd, Cd
d.
H
2
, Cd, H
2
Hint
11.
Which of the following must be true of a salt bridge?
a.
The salt bridge must prevent the flow of charged particles.
b.
The solutions joined by the salt bridge can mix freely.
c.
Ions can move through the salt bridge.
d.
The tube of the salt bridge must remain open.
Hint
12.
What is the numerical value for the standard cell potential for the following reaction? 2Cr
3+
aq
+3Cu
s
→2Cr
s
+3Cu
2+
aq
SC.B.1.4.2
a.
-1.08 V
b.
-0.40 V
c.
1.08 V
d.
0.40 V
Hint
