Electrolysis

Question 1

What is electrolysis?

Answer 1

Electrolysis is a chemical change caused by passing an electric current through a compound that is either molten or in solution. Electricity is used to split the compound into elements.

Question 2

What is the electrolyte?

Answer 2

The substance that undergoes electrolysis which must contain ions.

Question 3

What is the name of the negative electrode?

Answer 3

Cathode

Question 4

What is the name of the positive electrode?

Answer 4

Anode

Question 5

What does PANC stand for?

Answer 5

Positive Anode, Negative Cathode

Question 6

What happens at the cathode?

Answer 6

Positive ions (metals or H+) move here. When they reach the electrode, they gain electrons and are reduced to form the metal element or hydrogen gas.

Question 7

What happens at the anode?

Answer 7

Negative ions (typically non-metals) move here. When they reach the electrode, they lose
electrons and are oxidised to form the non-metal element.

Question 8

What does OIL RIG stand for?

Answer 8

Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons)

Question 9

What form to ionic compounds have to be in to undergo electrolysis? Why?

Answer 9

Molten or dissolved (typically in water). So that the ions are able to move.

Question 10

What happens when molten NaCl is electrolysed? Include half-equations.

Answer 10

Na+ ions are attracted to the cathode and gain electrons to be reduced to sodium metal:
Na+ + e- –> Na

Cl- ions are attracted to the anode and lose electrons to be oxidised to chlorine gas:
2Cl- –> Cl2 + 2e-