ES 3

Question 1

What is electrolysis?

Answer 1

decomposing a compound using an electric current

Question 2

What happens at the electrodes?

Answer 2

Electrons are lost or gained by ions

Question 3

Which is the negative electrode?

Answer 3

Cathode

Question 4

What are usually the products at the electrodes?

Answer 4

Cathode - metal
Anode - non-metal or hydrogen

Question 5

Where do cations and anions migrate to?

Answer 5

Cations -> cathode
Anions -> anode

Question 6

Why is it easier to carry out electrolysis do solution in aqueous state?

Answer 6

The ions become free to move

Question 7

What happens at the anode ?

Answer 7

Oxidation

Question 8

What happens to halide ions at the anode?

Answer 8

HAlogen is produced at the anode as they are oxidized more easily than water
2Cl- -> Cl2 + 2e-

Question 9

What happens to sulfates and nitrates at the anode?

Answer 9

Oxidized less easily than water so oxygen gas is produced at the anode
2H2O -> O2 + 4H+ + 4e-

Question 10

What happens to when the anode and metal solution are the same?

Answer 10

Metal anode loses mass as metal atoms change to ions and go into the solution

Question 11

What is produced when a group 1 or 2 metal is aluminium, is at the cathode?

Answer 11

Hydrogen
2H2O(l) + 2e- -> 2OH-(aq) + H2(g)

Question 12

What happens at the cathode if the solution is an acid?

Answer 12

Hydrogen is produced
2H+ (aq) + 2e- -> H2 (g)

Question 13

What happens if a less reactive metal (not group 1 or 2) is at the cathode?

Answer 13

Metal atoms are formed
Metal ion (aq) + electrons -> metal atom (s)