Question

Three experiments to study the process of rusting are given below. Observe the three test tubes and answer the following questions.
A. Why the nail in the test tube $$2$$ is not rusted?
B. Why is the nail in the test tube $$1$$ is rusted highly?
C. Would the nail in the test tube $$3$$ get rusted?

Answer 1

The essential requirement for corrosion are:

• Supply of oxygen
• Presence of water
• Material itself

(A) The nail in the test tube $$2$$ is not rusted because in test tube $$2$$, we take boiling water. So, all the dissolved oxygen is removed from the water and if the iron nail does not get a supply of oxygen then corrosion is not carried out.

(B) The nail in the test tube $$1$$ is rusted highly because in the test tube $$1$$, the iron nail meets all the requirements which are essential for the process of corrosion. That is the supply of oxygen in dissolved form, the presence of water and material itself.

(C) The nail in the test tube $$3$$ is not rusted because calcium chloride is one of the best absorbents. So, it absorbs all the dissolved oxygen present in water. Hence corrosion process does not take place.