5.5 Electrolysis

Question 1

What is electrolysis?

Answer 1

The breaking down of a compound using electricity

Question 2

What is the positive electrode called?

Answer 2

Anode

Question 3

What is the negative electrode called?

Answer 3

Cathode

Question 4

What are electrodes made of?

Answer 4

A soiled which conducts electricity but is inert (unreactive), usually graphite or platinum

Question 5

What is the electrolyte?

Answer 5

The substance to be broken down and it needs to conduct electricity

Question 6

What are the only compounds which can conduct electricity?

Answer 6

Ionic compounds which are molten or dissolved so the ions are free to move

Question 7

Why won’t solid ionic compounds work as electrolytes?

Answer 7

The ions can’t move

Question 8

Why won’t covalent compounds work as electrolytes?

Answer 8

Molecules are not charged

Question 9

What are the positive ions called and why?

Answer 9

Cations as they are attracted to the cathode

Question 10

What are the negative ions called and why?

Answer 10

Anions as they are attracted to the anode

Question 11

What does electrolysis of a molten ionic compound produce?

Answer 11

Its elements

Question 12

What happens at the anode?

Answer 12

Non-metal ions lose electrons to form molecules (neutral)

Question 13

What happens at the cathode?

Answer 13

Metal ions gain electrons to form atoms (neutral)

Question 14

What can be seen when chloride undergoes molten electrolysis at the anode?

Answer 14

Bubbles of play green gas

Question 15

What can be seen when magnesium undergoes molten electrolysis at the cathode?

Answer 15

Grey solid formed on surface of the cathode

Question 16

What is it called when water molecules break apart to form H+ and OH- ions?

Answer 16

Dissociating

Question 17

What happens during aqueous electrolysis to halide ions at the anode?

Answer 17

If present, that element is produced as normal

Question 18

What happens during aqueous electrolysis when halide ions are not present at the anode?

Answer 18

O2 and H2O are produced according to the half equation:
4OH- —–> O2 + 2H2O + 4e-

Question 19

What happens during aqueous electrolysis when the metal is less reactive than hydrogen at the cathode?

Answer 19

That element is produced as normal

Question 20

What happens during aqueous electrolysis when the metal ion is more reactive than hydrogen at the cathode?

Answer 20

H2 is produced according to the half equation:
2H+ + 2e- —–> H2

Question 21

What happens during aqueous electrolysis to the ions which did not reacts?

Answer 21

Remain leftover in the solution as the third product