Electrolysis

Question 1

What is the definition of electrolysis?

Answer 1

Splitting up substances by using electricity

Question 2

The _______ is ________, the _____ is _____. These are both known as electrodes

Answer 2

Cathode & negative
Anode & positive
Electrodes by definition are just solids that conduct electricity

Question 3

Why can’t an ionic solid be electrolysed?

Answer 3

Because the ions are in a fixed position, therefore cannot move

Question 4

The negative electrode will attract which ions?

Answer 4

Positive ions, just like the positive electrode will attract negative ions

Question 5

What is an electrolyte?

Answer 5

A liquid or solution that can conduct electricity

Question 6

Negative ions lose electrons. They become ________

Positive ions gain electrons. They become _______

Answer 6

Oxidised (e.g. 2Br- = Br2 + 2e-)

Reduced (e.g. Pb2+ + 2e- = Pb)

Question 7

Molten ionic compounds cannot be electrolysed. True or false?

Answer 7

False - they can be electrolysed. This is because they are able to move freely and conduct electricity

Question 8

Can metals be extracted from their Ores by using electrolysis?

Answer 8

Yes they can

Question 9

A student carries out electrolysis on molten sodium chloride. What is produced at the a) anode b) cathode?

Answer 9

a) Chlorine - because Cl is in group 7 so has 1 missing electron on its outer shell. Cl- will be attracted to the positive anode
b) Sodium - because Na is in group 1 so has 1 extra electron on its outer shell. Na+ will be attracted to the negative cathode

Question 10

What is added to some substance to reduce the melting point?

Answer 10

Cryolite