1. Which of the following substances is an electrolyte?
  • A.   copper metal
  • B.   solid sodium chloride
  • C.   copper chloride solution
  • D.   molten sugar
2. Which statement about the conduction of electricity by compounds is true?
  • A.   Covalent compounds conduct when liquid as molecules are free to move
  • B.   Ionic compounds conduct in aqueous solution as ions are free to move
  • C.   Covalent compounds do not conduct when solid as ions are not free to move
  • D.   Ionic compounds conduct when molten as electrons are free to move

3. What are the products of electrolysis of molten aluminium oxide ?

  Positive electrode Negative electrode
A aluminium oxygen
B aluminium hydrogen
C oxygen aluminium
D hydrogen aluminium

The diagram shows the apparatus used to electrolyse lead(II)bromide. The wires connected to the electrodes are made from copper. During electrolysis of the molten lead(II)bromide particles X , Y and Z move in the directions shown by the arrows.

electrolysis of lead bromide

4. Electrolysis does not occur until the lead(II)bromide is molten because when solid the ..
  • A.   electrons are not free to move
  • B.   electrons are free to move
  • C.   ions are not free to move
  • D.   ions are free to move
5. Particle X is a .
6. Particle Y is a .
7. Particle Z is a .

 Magnesium is extracted by electrolysis of molten magnesium chloride (MgCl2) obtained from sea water.


8. The half equation for the reaction occurring at the positive electrode is …

  • A.   Cl-  Cl + e-
  • B.   2Cl-  Cl2 + 2e-
  • C.   Cl- + e-  Cl  
  • D.   2Cl- + 2e- Cl2  

9.The half-equation for the reaction occurring at the negative electrode and the type of reaction occurring is:

  Half-equation Type of reaction
A Mg2+ Mg + 2e- oxidation
B Mg2+ Mg + 2e- reduction
C Mg2+ + 2e- Mg oxidation
D Mg2+ + 2e- Mg reduction