1. Which of the following statements about voltaic cells and electrolytic cells is false?
A. They are both types of electrochemical cells.
B. In voltaic cells, chemical energy is converted to electrical energy.
C. In electrolytic cells, the reactions are non-spontaneous.
D. Oxidation occurs at the cathode in a voltaic cell.
2. A voltaic cell is set up between a magnesium half-cell and a copper half-cell, as shown in the diagram below.
Which of the following statements is correct for this cell?
A. There are electrons flowing from the copper electrode to the magnesium electrode.
B. There is a net flow of positive ions from the salt bridge to the copper half-cell.
C. Copper is the anode of the voltaic cell.
D. Reduction occurs on the magnesium electrode.
3. Below is a diagram of a voltaic cell. M and N are metal electrodes placed in their respective salt solutions. M is higher up in the activity series than N.
Select the correct combination of half-equations at the electrodes of the cell.
Anode
Cathode
A.
M(s) → M2+(aq) + 2e-
N2+(aq) + 2e- → N(s)
B.
M2+(aq) + 2e- → M(s)
N(s) → N2+(aq) + 2e-
C.
N(s) → N2+(aq) + 2e-
M2+(aq) + 2e- → M(s)
D.
N2+(aq) + 2e- → N(s)
M(s) → M2+(aq) + 2e-
4. A voltaic cell has the cell notation:
Pt|H2(g)|H+(aq)||Fe3+(aq),Fe2+(aq)|Pt
Which row in this table correctly describes the equation and the location of Fe3+(aq), Fe2+(aq) ions?
Equation
Fe3+(aq), Fe2+(aq)
found at ...
A.
H2(g) + 2Fe3+(aq) → 2H+(aq) + 2Fe2+(aq)
anode
B.
H2(g) + 2Fe3+(aq) → 2H+(aq) + 2Fe2+(aq)
cathode
C.
2H+(aq) + 2Fe2+(aq) → H2(g) + 2Fe3+(aq)
anode
D.
2H+(aq) + 2Fe2+(aq) → H2(g) + 2Fe3+(aq)
cathode
5. Which of the following descriptions of an electrolytic cell is correct?
I. The anode is positive, and the cathode is negative.
II. Reduction occurs at the positive electrode and oxidation occurs at the negative electrode.
III. Electrons flow through the electrolyte.
A. I only
B. II only
C. I and III only
D. I, II and II
6. In the electrolysis of molten magnesium bromide MgBr2, what is the correct combination of half-equations at the electrodes?
Anode
Cathode
A.
Mg(l) → Mg2+(l) + 2e-
Br2(l) + 2e- → 2Br-(l)
B.
Mg2+(l) + 2e- → Mg(l)
2Br-(l) → Br2(l) + 2e-
C.
2Br-(l) → Br2(l) + 2e-
Mg2+(l) + 2e- → Mg(l)
D.
Br2(l) + 2e- → 2Br-(l)
Mg(l) → Mg2+(l) + 2e-
7. What are the products formed during the electrolysis of molten aluminium oxide?
Positive electrode
Negative electrode
A.
Al3+
O2-
B.
O2-
Al3+
C.
Al
O2
D.
O2
Al
8. A rechargeable lead-acid battery is often used in cars to start the engine. The reversible reactions during the charge and discharge of the battery are described by this equation:
2PbSO4(s) + 2 H2O(l)
Pb(s) + PbO2(s) + 2H2SO4(aq)
Shown below are 4 possible half-equations that might occur at an electrode:
What is the correct combination of half-equations that happen at the cathode and the anode during the discharge of the battery?
Cathode
Anode
A.
I
II
B.
II
I
C.
III
IV
D.
IV
III
9. In a hydrogen fuel cell, hydrogen reacts with oxygen to form water and electricity. If an alkaline electrolyte is used, which of the following is the half-equation at the cathode of the cell?
A. O2(g) + 4H+(aq) + 4e− → 2H2O(l)
B. O2(g) + 2H2(g) + 4e− → 2H2O(l)
C. H2(g) + 2OH−(aq) → 2H2O(l) + 2e−
D. O2(g) + 2H2O(l) + 4e− → 4OH−(aq)
10. Which of the following statements is correct about the fuel cell?
I. A fuel cell generates electrical energy from chemical energy.
II. A fuel cell has its fuel stored within the cell.
III. A fuel cell has an anode, a cathode and an electrolyte.
