Experiment: To measure the potential difference of a simple cell

Aim: To measure the potential difference of a simple cell when different electrodes are used

Materials: dilute sulphuric acid, voltmeter, beaker, leads and crocodile clips, magnesium ribbon,lead foil, copper foil, iron, sandpaper

Method

1. Place 75 cm of dilute sulphuric acid in a beaker
2. Clean each electrode with sandpaper
3. Coil the magnesium ribbon around a pencil
4. Dip a pair of electrodes into the sulphuric acid to about half their length
5. Lightly touch the electrodes with a pair of leads connected to a voltmeter
6. Always touch the least reactive metal electrode with the positive lead terminal of the voltmeter

Results and Observation

• A current flows when two different metals are used as electrodes
• The least reactive metal is the positive terminal
• The most voltage is obtained when the least reactive metal (copper) and
• The most reactive metal (magnesium) are used
• If the same metal is used no current flows and no voltage is recorded

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