Question

Take some clean iron nails and place them in the three test tubes prepared as under:

Test tube A: Contains boiled water and a thin layer of oil.

Test tube B: Contains dry air.

Test tune C: Testube half-filled with water.

All the test tubes are tightly closed after placing the nails. After some time what will you observe?

• A. Nails placed test tube A rust.
• B. Nails placed test tube B rust.
• C. Nails placed test tube C rust.
• D. None of these

Answer 1

The correct option is C Nails placed test tube C rust.

In test tubes A and B, corrosion of nails will not take place.

For corrosion to take place, air (or oxygen), water and iron, three should be in contact.

In test-tube A, a layer of oil separates air from nails and boiled distilled water.

In test-tube B, because the air is dry, hence no moisture is present which can cause rust.

In test-tube C, rusting of nails takes place, as it has all the conditions necessary for rusting i.e. presence of air(oxygen) and moisture.