CHEM 104 - Electrochemistry and Redox Exam 2026/2027 UPDATE
Portage Learning
1. In a redox reaction, what is the process of losing electrons called?
A. Reduction
B. Condensation
C. Hydrolysis
D. Oxidation
Answer: D
Rationale: Oxidation is defined as the loss of electrons by a molecule, atom, or ion, which
results in an increase in oxidation state.
2. What is the oxidation number of sulfur in the sulfate ion (SO4^2-)?
A. +4
B. -2
C. +6
D. +8
Answer: C
Rationale: Oxygen is usually -2. Four oxygens give -8. To have a net charge of -2, sulfur
must be +6 (+6 - 8 = -2).
,3. In a galvanic cell, at which electrode does oxidation occur?
A. Anode
B. Cathode
C. Salt Bridge
D. Platinum wire
Answer: A
Rationale: In both galvanic and electrolytic cells, oxidation always occurs at the anode (An
Ox).
4. Which of the following describes a reducing agent?
A. It accepts electrons and is reduced.
B. It donates electrons and is oxidized.
C. It donates electrons and is reduced.
D. It accepts electrons and is oxidized.
Answer: B
Rationale: A reducing agent causes reduction in another species by donating electrons;
therefore, it itself undergoes oxidation.
5. What is the purpose of a salt bridge in a voltaic cell?
A. To allow electrons to flow between the electrodes.
B. To act as a catalyst for the redox reaction.
C. To increase the voltage of the cell.
D. To provide a path for ions to flow and maintain electrical neutrality.
Answer: D
Rationale: The salt bridge allows for the migration of ions to balance the charge buildup
that occurs as electrons flow through the external circuit.
, 6. In the shorthand notation for a cell, Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s), what
does the double vertical line represent?
A. The anode
B. The salt bridge
C. A phase boundary
D. The external wire
Answer: B
Rationale: In cell notation, a single line represents a phase boundary, while a double line
represents the salt bridge.
7. Which value of E°cell indicates a spontaneous reaction under standard
conditions?
A. E°cell = 0
B. E°cell < 0
C. E°cell > 0
D. E°cell = -1.0V
Answer: C
Rationale: For a spontaneous reaction in a galvanic cell, the standard cell potential must be
positive.
8. The standard reduction potential (E°) for Zn2+ + 2e- -> Zn is -0.76 V and for
Cu2+ + 2e- -> Cu is +0.34 V. What is the standard cell potential (E°cell)?
A. -0.42 V
B. +0.42 V
C. +1.10 V
D. -1.10 V
Answer: C
Rationale: E°cell = E°cathode - E°anode. Since Cu has the higher potential, it is the cathode.
E°cell = 0.34 - (-0.76) = +1.10 V.
Portage Learning
1. In a redox reaction, what is the process of losing electrons called?
A. Reduction
B. Condensation
C. Hydrolysis
D. Oxidation
Answer: D
Rationale: Oxidation is defined as the loss of electrons by a molecule, atom, or ion, which
results in an increase in oxidation state.
2. What is the oxidation number of sulfur in the sulfate ion (SO4^2-)?
A. +4
B. -2
C. +6
D. +8
Answer: C
Rationale: Oxygen is usually -2. Four oxygens give -8. To have a net charge of -2, sulfur
must be +6 (+6 - 8 = -2).
,3. In a galvanic cell, at which electrode does oxidation occur?
A. Anode
B. Cathode
C. Salt Bridge
D. Platinum wire
Answer: A
Rationale: In both galvanic and electrolytic cells, oxidation always occurs at the anode (An
Ox).
4. Which of the following describes a reducing agent?
A. It accepts electrons and is reduced.
B. It donates electrons and is oxidized.
C. It donates electrons and is reduced.
D. It accepts electrons and is oxidized.
Answer: B
Rationale: A reducing agent causes reduction in another species by donating electrons;
therefore, it itself undergoes oxidation.
5. What is the purpose of a salt bridge in a voltaic cell?
A. To allow electrons to flow between the electrodes.
B. To act as a catalyst for the redox reaction.
C. To increase the voltage of the cell.
D. To provide a path for ions to flow and maintain electrical neutrality.
Answer: D
Rationale: The salt bridge allows for the migration of ions to balance the charge buildup
that occurs as electrons flow through the external circuit.
, 6. In the shorthand notation for a cell, Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s), what
does the double vertical line represent?
A. The anode
B. The salt bridge
C. A phase boundary
D. The external wire
Answer: B
Rationale: In cell notation, a single line represents a phase boundary, while a double line
represents the salt bridge.
7. Which value of E°cell indicates a spontaneous reaction under standard
conditions?
A. E°cell = 0
B. E°cell < 0
C. E°cell > 0
D. E°cell = -1.0V
Answer: C
Rationale: For a spontaneous reaction in a galvanic cell, the standard cell potential must be
positive.
8. The standard reduction potential (E°) for Zn2+ + 2e- -> Zn is -0.76 V and for
Cu2+ + 2e- -> Cu is +0.34 V. What is the standard cell potential (E°cell)?
A. -0.42 V
B. +0.42 V
C. +1.10 V
D. -1.10 V
Answer: C
Rationale: E°cell = E°cathode - E°anode. Since Cu has the higher potential, it is the cathode.
E°cell = 0.34 - (-0.76) = +1.10 V.
