10 minutes maximum

An IB Periodic Table is required.

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. The diagram shows a zinc / iron voltaic cell.

magnesium + copper half cells- electrolysis

What are the labels 1-4 showing?

  Anode Cathode Voltmeter Salt Bridge
A. 4 2 3 1
B. 4 2 1 3
C. 2 4 1 3
D. 2 4 3 1

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.

magnesium + copper half cells- electrolysis

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:


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. In a voltaic cell, consisting of a copper half-cell and a zinc half-cell, what would happen to the zinc electrode size, and the colour or the copper sulphate solution?

  Zinc electrode size cupper sulphate solution colour
A. increase more blue
B. increase less blue
C. decrease more blue
D. decrease less blue

6. A voltaic cell is set up between a magnesium half-cell and a copper half-cell, as shown in the diagram below.

magnesium + copper half cells- electrolysis

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.

7. 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-

8. 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 III

9 In the electrolysis of molten zinc chloride using inert graphite electrodes, where will zinc crystals and bubbles of gas be formed?

  Zinc crystals formed Bubbles of gas formed
A. anode anode
B. anode cathode
C. cathode anode
D. cathode cathode

10. 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