Review of basic electrolytic cells – molten electrolytes

Question 1

What is electrolysis?

Answer 1

Electrolysis is the use of electricity to chemically decompose a compound into its component elements.

Question 2

The ionic compound must be ____ (or in solution) to break apart the ionic bonds and allow the ions to move freely in the ____ and therefore complete the circuit.

Answer 2

molten

electrolyte

Question 3

• The positive electrode attracts the ____ ions in solution and due to the presence of the power supply, pulls the “extra” electrons away from the negative ion, thus causing ____.
• The negative electrode attracts the ____ ions in the solution and due to the excess of electrons on its surface (from the external circuit), the positive ions gain electrons and are ____.

Answer 3

negative
oxidation
positive
reduced

Question 4

The electrons travel through the ___ circuit only and move from the positive electrode to the negative electrode.

Answer 4

external

Question 5

There is a flow of ions through the liquid, as positive ions migrate towards the negative electrode (cathode) and negative ions migrate towards the positive electrode (anode). This flow of ions through the liquid is called
_____ _____.

Answer 5

electrolytic conduction

Question 6

Give 3 reasons why graphite electrodes are suitable.

Answer 6

Good electrical conductor
Inert/unreactive/not readily oxidised or reduced
High melting point (OR solid at high temp)

Question 7

Explain why one has to either melt or dissolve the solid NaCl in order to electrolyse it in each of the respective cells.

Answer 7

In order to free the ions from the crystal lattice so that it would conduct electricity.