Experiment to Demonstrate Rusting

Materials: 6 pieces of nails, 3 test tubes, water, cotton wool, calcium chloride, liquid paraffin, Bunsen burner, 2 pieces of bungs.

Method:

Set up the apparatus shown on the figure below. Leave the set up for some days (7 – 10 days). After the days, observe what happened to the nails in the 3 test tubes.

Observation

The nails in test tube A and B show no reddish brown layer (rust) on their surfaces. This is due to the absence of moisture (water) in the test tube A and there was no air (oxygen) in test tube B.

The iron nails in test tube C develop some reddish brown layer on their surfaces. This was due to the presence of oxygen (air) and moisture (water).

Conclusion

The presence of air and water corrode iron or causes iron to rust.

image

NB:

The water in the test tube B was boiled and cooled in order to remove oxygen in the water.

The liquid paraffin prevented air from dissolving in the water in test tube B. Calcium Chloride removed water in test tube A.