Question

With the help of an activity, explain the conditions under which iron articles get rusted.

Answer 1

To demonstrate the conditions required for rusting, take three test tubes and place an iron nail in each. In the first test tube, add water and keep it open to allow air to enter. In the second test tube, add boiled water and cover it with a layer of oil to prevent air from dissolving. In the third test tube, place calcium chloride to absorb moisture and seal it with a cotton plug to prevent water entry. After a few days, observe the nails. The nail in the first test tube rusts because both air (oxygen) and water are present. The nails in the second and third test tubes do not rust, as one of the essential conditions (air or water) is absent. This shows that iron rusts only when both air and water are present.