Eleceolysis

Question 1

What is the anode

Answer 1

Positively charged electrode

Question 2

What is the cathode

Answer 2

Negatively charged electrode

Question 3

How to figure out what is made at cathode (aqueous solution’)

Answer 3

If the +ve ion is more reactive than hydrogen, then the substance produced will be hydrogen if not then it’s the substance

Question 4

How to figure out what is made at anode (aqueous solution)

Answer 4

If the +ve ion is halide (group 7), then it is produced, if not then oxygen is produced from the hydroxide ions

Question 5

How are electrolysis products of ionic compounds can be different in the molten or aqueous states.

Answer 5

-> in aqueous state there is water meaning H+ and OH- ions are present
-> in molten states there is no water meaning there are no H+ and OH- ions present

Question 6

A student investigates the electrolysis of aqueous solutions of ionic compounds.

Why is it important that the investigation is done with inert electrodes?

Answer 6

Inert electrodes are unreactive and do not react with the electrolyte

Question 7

Why cannot solid aluminium oxide be electrolysed

Answer 7

Ions cannot move in solid state

Question 8

Meena does electrolysis by electrolysis copper for 30 seconds and immediately weighs it to find weight change

How could she improve her experiment

Answer 8

• electrolyse it for longer than 30 seconds as there will be insufficient change at electrodes
• anode and cathode need to be washed and dried before being weighed

Question 9

• the cathode gains mass
• the anode loses mass.
Explain these observations in terms of the reactions at each electrode. (Electrolysis of copper)

Answer 9

-> copper is deposited at cathode
-> copper is dissolved at anode

Cu2+ + 2e- —> Cu
Cu - 2e- —> Cu2+