W1 Oct C-S4D Pure Chem Electrolysis Revision

A student set up three different electrochemical cells containing two of the following metals, W, Y or Z. The following table shows the positive terminal and voltage measured in the cell.

Which of the following shows the correct order of reactivity?

• W > Y > Z

• W > Z > Y

• Y > W > Z

• Z > Y > W

An electrolysis experiment was conducted on liquid Y using inert electrodes. The following diagrams show the state of the setup before and after the cell was turned on.

Which could not be the possible identity of liquid Y?

• aqueous copper(II) sulfate

• aqueous sodium nitrate

• dilute sulfuric acid

• molten sodium chloride

The apparatus shown is set up to plate a steel key with copper. The key does not get coated with copper.

What needs to be changed in order for the key to be successfully plated with copper?

• Increase the concentration of the aqueous copper(II) sulfate.

• Increase the voltage of the battery used.

• Replace the solution with dilute sulfuric acid.

• Reverse the electrical connections.

The following diagram shows the electrolysis of molten lithium chloride.

Write the ionic half equation occurring at the anode.

The following diagram shows the electrolysis of molten lithium chloride.

Write the ionic half equation occurring at the cathode.

The following diagram shows a simple cell.

What is the overall reaction occurring in the cell?

Suggest one other way by which the voltage measured can be increased.