What is rusting of iron

Today we will find the answer to what is rusting of iron. This phenomenon is very common. We will discuss the causes, prevention, and harmful effects of rusting of iron.

Rusting of iron is an example of corrosion, which is a harmful phenomenon.

Rusting of iron

Rusting of iron

The process of eating away metals by the action of atmospheric reagents changing the metal into its compound is called rusting.

 

Rusting of iron is a type of corrosion that results in a flaky layer on iron or iron objects known as rust. Iron rust formula is `Fe_2O_3.nH_2O`

Rust is a hydrated ferric oxide that is brownish-orange in colour.

Rusting  of iron reaction

`4Fe   + 3O_2  +  n.H_2O → 2Fe_2O_3.nH_2O`

 

The chemical reaction of rusting of iron

During rusting, a redox reaction of iron takes place, and hydrated iron oxide is formed.

Oxidation reaction: - Iron is oxidized as it loses electrons

`Fe    →   Fe^(2+)  + 2e^-`

These electrons are used to reduce the oxygen dissolved in water.

Reduction reaction:- Oxygen is reduced as it gains electrons

`Fe^(2+)  + 2OH^-    →  Fe(OH)_2   + Fe_2O_3` 

 Rusting of iron involves following electrochemical reactions.

The reaction produces hydrated iron (III) oxide, also known as rust.

Due to the presence of moisture, the oxygen atom increases the oxidation state of iron

 `4Fe^(2+) + O_2 → 4Fe_(3+) + 2O^(2-)`

Now iron cation and water molecules undergo the following reaction

 

`Fe^(2+) + 2H_2O ⇌ Fe(OH)_2 + 2H^+`

`Fe^(3+) + 3H_2O ⇌ Fe(OH)_3 + 3H^+`

 

Iron hydroxides are produced by the reaction between iron cations and hydroxyl ions

The reactions are as follows

`O_2 + 4H_2O + 4e– → 4OH^-`

 

`Fe^(2+) + 2OH^– → Fe(OH)_2`

 

`Fe^(3+) + 3OH^– → Fe(OH)_3`

Now following chemical reactions takes place. Hydroxides of iron undergo dehydration to produce iron oxides.

`Fe(OH)_2 ⇌ FeO + H_2O`

`4Fe(OH)_2 + O_2 + xH_2O → 2Fe_2O_3.(x+4)H_2O`

`Fe(OH)_3 ⇌ FeO(OH) + H_2O`

`FeO(OH) ⇌ Fe_2O_3 + H_2O`

 

Conditions necessary for rusting

Rusting of iron takes place in the following conditions

    1.  Open surface of a metal

    2.  Presence of oxygen(air)

    3.  Presence of moisture(water)

Harmful effects of rusting

 

Rusting can cause the following harms

    1.  Weakening of metal (iron)

    2.  Make iron objects brittle

    3.  Surface of iron objects becomes rough

    4.  Reduce its appearance and value

    5.  Iron objects get holes or cavities

Prevention of rusting of iron

Rusting causes damage to iron and iron articles, so they must be prevented. Rusting of iron can be prevented by following methods

    

    1.  Oiling, painting, and greasing: - When the iron surface is exposed to the atmosphere, it undergoes rusting, so applying paint on the surface prevents oxygen and moisture from coming in contact with the metal surface.

         Oiling and greasing also prevent oxygen and moisture from attacking the metal surface.

   

    2.  Galvanisation: -   This process involves coating iron articles with a layer of zinc. The process is known as galvanization.

    

    3.  Applying red oxide (`Fe_2O_3`) also prevents iron from rusting.

 

Related Topics

1. What happens during a chemical reaction

FAQs

1.  Rusting of iron is which change?

Ans.- Rusting of iron is a chemical change known as corrosion that forms a new compound called ‘rust’.

 

2.  What is the iron rust formula?

Ans.- `Fe_2O_3.nH_2O`

3.  How to prevent rusting?

Ans.- Rusting can be prevented by applying oil, grease, or paint on iron articles and also by galvanization.

4.  what kind of reaction is rusting of iron?

Ans.- Rusting of iron is a redox reaction.

5.  what kind of change is rusting of iron?

Ans. - Rusting of iron is a chemical change because it is irreversible.

6. What is the chemical name of rust of iron?

Ans. – Hydrated iron oxide

7.  What is rusting of iron?

Ans.- Rusting of iron is a type of corrosion. When iron comes in direct contact with oxygen and moisture, forms hydrated iron oxide(rust).

8.  What are the conditions necessary for rusting iron?

Ans. - The presence of oxygen, the open surface of the metal, and moisture are the necessary conditions for rusting of iron.

9.  What are the harmful effects of rusting?

Ans.- Rusting of iron makes metal weak, brittle, and rough.

10.    Is rusting of iron corrosion?

Ans.- Yes, rusting of iron is a type of corrosion.