C6.4 Electrolysis of aqueous solution

Question 1

What is brine?

Answer 1

Concentrated sodium chloride solution

Question 2

What are the products when brine is electrolyzed?

Answer 2

Chlorine
Hydrogen
Sodium hydroxide solution

Question 3

What happens at the anode of the electrolysis of brine?

Answer 3

Cl- ions and OH- are both attracted to the anode

Since a halide ion is present this means chlorine is produced at the anode

Question 4

What is the half equation at the anode of the electrolysis of brine?

Answer 4

2Cl- → Cl(2) molecule + 2e-

Question 5

What happens at the cathode of the electrolysis of brine?

Answer 5

H+ ions and Na+ ions are attracted to the cathode

Sodium is more reactive than hydrogen so hydrogen is formed at the cathode

Question 6

What is the half equation at the cathode of the electrolysis of brine?

Answer 6

2+H + 2e- → H(2) molecule

Question 7

What is the remaining solution after the completed electrolysis of brine?

Answer 7

Sodium hydroxide

Question 8

How can you test for the NaOH solution?

Answer 8

Add a Ph indicator

It will be blue or purple if the solutions contains a base