Question

ASSERTION
Corrosion of iron is commonly known as rusting.
REASON
Corrosion of iron occurs in the presence of water and air.
A) Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
B) Both Assertion and Reason are correct and Reason is not the correct explanation of assertion.
C) Assertion is correct but Reason is incorrect.
D) Both Assertion and Reason are correct.

Answer 1

Hint: Corrosion - The process of slowly eating away the metal due to attack of the atmospheric gases on the surface of the metal resulting into the formation of compounds such as oxides, sulfides, carbonates, sulfates etc. is called corrosion.

Complete answer:
The most common example of corrosion is the rusting of iron. Rust can also affect iron alloys such as steel. The rusting of iron can also occur when iron reacts with chloride in an oxygen-deprived environment, while green rust, which is another type of corrosion, can be formed directly from metallic iron or iron.
The water vapors and air are responsible for the formation of rust because they react with the surface of metal by which corrosion occurs. Rusting of iron involves an increase in the oxidation state of iron, accompanied by a loss of electrons. Oxygen is a very good oxidizing agent whereas iron is a reducing agent. Therefore, the iron atom readily gives up electrons when exposed to oxygen.
In presence of water and air, iron is converted into hydrated ferric oxide.
\[4Fe + 3{O_2} \to 2F{e_2}{O_3} \\
4Fe + 3{O_2} + x{H_2}O{\text{ }} \to {\text{ }}F{e_2}{O_3}.x{H_2}O\]
Both the statements are correct and independent of each other.

So the correct answer is option B.

Note: Corrosion occurs in a wide range of objects. Corrosion includes rusting and Rust will increase and speed up the corrosion process. Corrosion can occur when the substance is exposed to air or some chemicals. Rusting mainly occurs when a metal is exposed to air and moisture.