Electrolysis

Question 1

What is an electrolyte?

Answer 1

An electrolyte is a liquid or a solution that contains ions so can conduct electricity. This means the Ions can move to the electrodes.

Question 2

What is the positive electrode?

Answer 2

Anode

Question 3

What is the negative electrode?

Answer 3

Cathode

Question 4

Why are solid iionic compounds dissolved in water before electrolysis?

Answer 4

• It requires less energy to dissolve the compounds in water than melt them.
• However in the electrolysis of solutions the pure elements are not always produced.

Question 5

What happens at the anode in the electrolysis of a solution?

Answer 5

• The OH- ions formed from the ionisation of water are attracted to the anode and form oxygen gas.
• If the non-metal ion is a halogen then that gas is formed.
• 4OH- –> O² + 2H²O + 4e-
• 2CL- –> CL² + 2e-

Question 6

What happens at the cathode in the electrolysis of a solution?

Answer 6

• If the metal is more reactive than hydrogen than it is formed at the cathode.
• The H+ ions from the ionisation of water are attracted to the cathode.
• 2H+ + 2e- –> h²
• The metal ions remain in solution.

Question 7

What does PANIC mean?

Answer 7

Positive
Anode
Negative
Is
Cathode