Predicting Products of Electrolysis

Question 1

Describe why an ionic solid can’t be electrolysed.

Answer 1

The ions are in fixed positions, therefore they can’t carry a charge and conduct electricity

Question 2

Describe when an ionic compound can conduct electricity.

Answer 2

An ionic compound can conduct electricity when molten or dissolved in water

Question 3

Which ions are present in aqueous solutions?

Answer 3

• Hydrogen ions (H+)
• Hydroxide ions (OH-)

Question 4

When will hydrogen gas be produced at the cathode from an aqueous solution?

Answer 4

When the metal is more reactive than hydrogen in the reactivity series

Question 5

What will be produced at the cathode if the metal is less reactive than hydrogen?

Answer 5

A solid layer of the pure metal will be produced

Question 6

When will halogen atoms be produced at the anode from an aqueous solution?

Answer 6

When halide ions are present

Question 7

What will happen at the anode when no halide ions are present?

Answer 7

Oxygen will be formed

Question 8

(Exam-style question)

Answer 8