Electrochemical process:

An electrochemical cell is set up using a platinum and nickel electrodes and dilute solutions of potassium permanganate and nickel nitrate. As the reaction proceeds the purple solution fades and the green solution deepens in colour. One electrode becomes thinner. If a voltmeter is connected to the wires a voltage is recorded.

Electrolytic process:

A silver rod and copper ring are dipped into a colorless solution of silver nitrate. Both the copper ring and silver rod are joined by wires to a battery. As the reaction proceeds, the reddish-brown copper ring thickens and slowly becomes shiny grey.

Write a report explaining why the reaction in the electrolytic cell is non-spontaneous and requires energy to be supplied, whereas the reaction in the electrochemical cell is spontaneous. In your report:

• link observations to species involved in the reactions
• identify the oxidant and the reductant as well as the oxidation and reduction reactions and justify these by referring to oxidation number changes and loss or gain of electrons.
• write balanced half and full oxidation-reduction equations
• elaborate on the oxidation-reduction processes. Your answer should include links between observations, equations and calculations.
• calculate cell potentials and compare relative strength of oxidants using data provided to predict spontaneity of reaction.