To study the process of rusting, Bharti set up the following experiment.

After a few days she concluded
I. Iron nails of tube Y get rusted as both water and air are present in it.
II. Iron nails of tube X do not get rusted as only dry air is present in it.
III. Iron nails of tube Z do not get rusted as air does not come in contact with nails.
Which of the results are correct?

Options

A. Only I
B. Only II
C. Only III
D. I, II and III

Answer

D

Explanation

For rusting, the presence of both oxygen and water is essential.
In tube Y, since both water and air are present, iron nails get rusted.
In tube X, since only dry air is present, iron nails do not get rusted.
In tube Z, layer of oil prevents air from dissolving in water. Since only water is present, iron nails do not get rusted.