C12 Electrolysis

What is electrolysis

Ionic compound is decomposed by electric current

Electrodes are often made of inert materials such as

Graphite / platinum

Why does the power supply have to be dc

Current passes in one direction only - act as electron pump

Where do electrons enter the electrolytic cell

Cathode (-ve electrode)

Where do electrons leave the electrolytic cell

Anode (+ve electrode)

Which direction do electrons flow through the external circuit

From anode to cathode

What is electroplating

Use of electrolysis to coat a cheap metal with a more expensive/protective one

In electroplating, at which electrode is the object being plated

Cathode

In electroplating, at which electrode is the substance coating the object

Anode

In electroplating, what is at the cathode

Object being plated

In electroplating, what is at the anode

Substance coating the other one

What is special about the anode in electroplating

Not inert

Can the electrolyte also supply ions for electroplating

Yes

In electroplating what happens to concentration of coating ions in the electrolyte and why

Conc is unchanged as coating element undergoes opposite reaction at cathode and anode

What is electrolytic refining used for

Purification of copper

In purification of copper, what is at the cathode

Pure copper

What supplies copper ions for electrolysis in purification of copper

Anode and electrolyte (copper ii sulfate)

In purification of copper, what is found at the anode

Impure copper

What happens at the anode in purification of copper

Cu2+ ions form

What happens at the cathode in purification of copper

Cu2+ ions are reduced to copper atoms which are plated onto the pure copper cathode