IG_Electrolysis I-III

Which reactions could take place at the anode during electrolysis?

 

1  4OH^–(aq) → 2H₂O(I) + O₂(g) + 4e^–

2  2Cl^–(aq) → Cl₂(g) + 2e^–

3  Cu²⁺(aq) + 2e^– → Cu(s)

4  2H⁺(aq) + 2e^– → H₂(g)

• 1 and 2

• 1 and 4

• 2 and 4

• 3 and 4

The diagram shows a method used to copper-plate a panWhich equation represents the reaction at the cathode?

• Cu²⁺ + 2e^– → Cu

• 2H⁺ + 2e^– → H₂

• 4OH^– → O₂ + 2H₂O + 4e^–

• 2O^2– → O₂ + 4e^–

What is the ionic half-equation for the reaction that occurs at the cathode when molten lead(II) bromide is electrolysed?

• Pb²⁺ + 2e^– → Pb

• 2Br^– → Br₂ + 2e^–

• Br₂ + 2e^– → 2Br^–

• Pb → Pb²⁺ + 2e^–

In separate experiments, electricity was passed through concentrated aqueous sodium chloride and molten lead(II) bromide.

What would happen in both experiments?

• A halogen would be formed at the anode

• A metal would be formed at the cathode

• Hydrogen would be formed at the anode.

• Hydrogen would be formed at the cathode

Which statements about the electrolysis of concentrated copper(II) chloride are correct?

1  Electrons are transferred from the cathode to the copper(II) ions.

2  Electrons move round the external circuit from the cathode to the anode.

3  Chloride ions are attracted to the anode.

4  Hydroxide ions transfer electrons to the cathode.

• 1 and 3

• 1 and 4

• 2 and 3

• 2 and 4

Four solutions are separately electrolysed

In which two experiments is a colourless gas evolved at the anode?

• 1 and 2

• 1 and 4

• 2 and 3

• 3 and 4

Which statement about electrolysis is correct?

• Electrons move through the electrolyte from the cathode to the anode.

• Electrons move towards the cathode in the external circuit.

• Negative ions move towards the anode in the external circuit.

• Positive ions move through the electrolyte towards the anode during electrolysis.

Which statements about the electrolysis of concentrated copper(II) chloride are correct?

 

1  Electrons are transferred from the cathode to the copper(II) ions.

2  Electrons move round the external circuit from the cathode to the anode.

3  Chloride ions are attracted to the anode.

4  Hydroxide ions transfer electrons to the cathode.

• 1 and 3

• 1 and 4

• 2 and 3

• 2 and 4

A solution of copper(II) sulfate can be electrolysed using copper electrodes or carbon electrodes.

Which statements are correct?

1  Using copper electrodes, oxygen gas forms at the anode.

2  Using copper electrodes, copper atoms lose electrons at the anode.

3  Using carbon electrodes, copper metal forms at the cathode.

4  Using carbon electrodes, copper ions gain electrons at the cathode.

• 1 and 2

• 1 and 3

• 2, 3 and 4

• 4 only

Dilute sulfuric acid is electrolysed using inert electrodes.

What are the ionic half-equations for the reactions that take place at each electrode?

• A

• B

• C

• D