10 minutes maximum! |
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1. The products at the electrodes in the electrolysis of molten potassium iodide are:
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Product at negative electrode |
Product at positive electrode |
| A |
potassium |
iodine |
| B |
potassium |
iodide |
| C |
iodine |
potassium |
| D |
iodide |
potassium |
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Q2-5. Electrolysis of molten lead bromide is carried out using the following circuit:
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2. The current is carried around the circuit by:
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In molten lead bromide |
In the wires |
| A |
electrons |
ions |
| B |
electrons |
electrons |
| C |
ions |
ions |
| D |
ions |
electrons |
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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
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4. The balanced half-equation and the type of reaction occurring at the negative electrode is:
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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 |
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5. The balanced half-equation and the type of reaction occurring at the positive electrode is:
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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 |
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Q6-7. Four substances were dissolved in water and connected in turn into the circuit below.
The results are shown in the table:
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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 |
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6. Which solution could be sulphuric acid? |
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7. Which solution could be copper(II)nitrate ? |
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Q8-9.
The electrolysis of a concentrated solution of sodium chloride produced two gases, X and Y :
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8. The identity of gas X and a test to confirm its identity is ……
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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 |
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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
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10. Aluminium is extracted by the electrolysis of molten aluminium oxide, Al2O3.
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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- |
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