Microscale electrolysis of copper (II) chloride

Using pencil leads as electrodes it is possible to carry out electrolysis experiments at school on a very small scale or micro-scale. The advantages of microscale are reduced equipment needs and environmental burden, speed, simplicity and safety.

The picture below shows the equipment used in a microscale electrolysis experiment on copper (II) chloride solution. This is modelled on the same electrolysis experiment described by Bob Worley on Microchemuk.

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Microscale electrolysis on a plastic sheet placed on a white tile

A movie showing how the experiment was set up and carried out can be seen here on You Tube.  A close-up of the experiment just before the power pack was turned on (6v d.c.) is shown below, complete with labels.

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Funny face labels

Here’s a gif animation of the electrolysis experiment:

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Face the changes

The results of the experiment:

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Face change, what happened?

Questions

1. What was the gas produced at the anode?

2. What was the solid produced at the cathode?

3. Why did the blue litmus paper turn pink and then white?

4. Why did the potassium iodide turn orange / brown?

5. Why did the potassium bromide turn yellow / orange?

6. Why did the blue colour of the copper (II) chloride fade?

Answers next time.

Go microscale!