10 minutes maximum! Can you do it in 5?

1. The products at the electrodes in the electrolysis of molten potassium iodide are:

  Product at negative electrode Product at positive electrode
A potassium iodine
B potassium iodide
C iodine potassium
D iodide potassium


Q2-5. Electrolysis of molten lead bromide is carried out using the following circuit:

lead bromide electrolysis


2. The current is carried around the circuit by:

  In molten lead bromide In the wires
A electrons ions
B electrons electrons
C ions ions
D ions electrons
3. The bulb will not light when lead bromide is solid because ...
  • A. solid lead bromide is covalently bonded
  • B. solid lead bromide is too tightly packed for electrons to get through
  • C. the ions in solid lead bromide are not free to move around
  • D. the atoms in solid lead bromide are not free to move around

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

  Half-equation at negative electrode Type of reaction
A Pb2+ Pb + 2e- reduction
B Pb2+ Pb + 2e- oxidation
C Pb2+ + 2e-  Pb reduction
D Pb2+ + 2e- Pb oxidation

5. The balanced half-equation and the type of reaction occurring at the positive electrode is:

  Half-equation at positive electrode Type of reaction
A 2Br- + 2e-   Br2 reduction
B 2Br- Br2  +  2e- oxidation
C Br-  Br  +  e- oxidation
D Br-  +  e-    Br reduction

Q6-7.   Four substances were dissolved in water and connected in turn into the circuit below.

electrolysis of solutions

The results are shown in the table:

  Current /A Product at cathode (-) Product at anode (+)
A 0.6 copper chlorine
B 0.6 copper oxygen
C 1.1 hydrogen oxygen
D 0.9 hydrogen chlorine


6. Which solution could be sulphuric acid?

7. Which solution could be copper(II)nitrate ?

The electrolysis of a concentrated solution of sodium chloride produced two gases, X and Y :

electrolysis of sodium chloride


8. The identity of gas X and a test to confirm its identity is:

  Gas X Test to confirm identity of gas X
A chlorine Turns damp blue litmus paper red
B chlorine bleaches damp blue litmus paper to white
C oxygen Relights a glowing splint
D oxygen Ignites with a pop with a burning splint
9. The correct half-equation for the formation of gas Y is:
  • A. H+ + e-  H
  • B. 2H+ + 2e- H2
  • C. 2H+H2 + 2e-
  • D. Na+ + e-  Na

10. Aluminium is extracted by the electrolysis of molten aluminium oxide, Al2O3.

  Product at cathode Equation at anode
A aluminium 2O2-   O2 + 4e-  
B aluminium O2-   O + 2e-  
C oxygen Al3+ + 3e-   Al
D oxygen Al3+  Al + 3e-