Reaction of Iron with Dilute Sulphuric Acid

When iron reacts with dilute sulphuric acid, a chemical reaction takes place which can be represented by the following balanced equation:

Fe (s) + H2SO4 (aq) → FeSO4 (aq) + H2 (g)

This reaction is a redox reaction, where iron is oxidized and hydrogen ions from sulphuric acid are reduced. Let's analyze the reaction in detail:

1. Dissociation of sulphuric acid:
Dilute sulphuric acid (H2SO4) dissociates into hydrogen ions (H+) and sulphate ions (SO4^2-) in water. This dissociation is important for the subsequent steps of the reaction.

2. Oxidation of iron:
Iron (Fe) reacts with hydrogen ions (H+) from the acid to form ferrous ions (Fe^2+) and liberate hydrogen gas (H2). This is an oxidation-reduction reaction, where iron loses electrons and is oxidized.

Fe (s) → Fe^2+ (aq) + 2e^-

3. Reduction of hydrogen ions:
The hydrogen ions (H+) from the sulphuric acid are reduced by gaining electrons from the iron atoms. They form hydrogen gas (H2) as a product of the reaction.

2H+ (aq) + 2e^- → H2 (g)

4. Formation of iron sulfate:
The ferrous ions (Fe^2+) produced in the reaction combine with sulphate ions (SO4^2-) from the sulphuric acid to form iron sulfate (FeSO4), which is a soluble salt.

Fe^2+ (aq) + SO4^2- (aq) → FeSO4 (aq)

Overall Reaction:
Combining all the steps, the overall reaction can be represented as:

Fe (s) + H2SO4 (aq) → FeSO4 (aq) + H2 (g)

Observations:
During the reaction, several observations can be made:

1. Effervescence: Hydrogen gas is liberated during the reaction, leading to the formation of bubbles or effervescence.
2. Color change: The color of the solution changes from clear to pale greenish-brown due to the formation of iron sulfate.
3. Heat evolution: The reaction is exothermic and releases heat.
4. Iron dissolves: The iron solid gradually dissolves in the acid as the reaction progresses.

Conclusion:
In conclusion, when iron reacts with dilute sulphuric acid, it undergoes oxidation and forms iron sulfate, while hydrogen gas is liberated. This reaction is important in various industrial processes and is also used in the laboratory to generate hydrogen gas.