When sulphur dioxide (SO2) reacts with oxygen (O2) and water (H2O) in the presence of a catalyst, sulphuric acid (H2SO4) is produced. This is a crucial chemical transformation, often observed in industrial processes and atmospheric chemistry.
The Reaction Process
This specific reaction is a key step in the industrial production of sulphuric acid, one of the most widely used chemicals globally. The presence of a catalyst is essential, as it speeds up the reaction without being consumed itself.
The chemical equation for this reaction is:
2SO2(g) + O2(g) + 2H2O(l) ⟶ 2H2SO4(aq)
Let's break down the components of this reaction:
- Reactants:
- Sulphur Dioxide (SO2): A gas, often a byproduct of burning fossil fuels or volcanic activity.
- Oxygen (O2): A gas, readily available in the atmosphere.
- Water (H2O): A liquid, essential for the formation of the acid.
- Products:
- Sulphuric Acid (H2SO4): A strong, highly corrosive mineral acid.
The table below summarizes the key aspects of this reaction:
| Component | Description | State |
|---|---|---|
| Sulphur Dioxide | Starting material, gaseous pollutant | Gas |
| Oxygen | Necessary reactant, atmospheric gas | Gas |
| Water | Essential for acid formation | Liquid |
| Catalyst | Accelerates reaction (e.g., vanadium(V) oxide) | N/A |
| Sulphuric Acid | Primary product, strong acid | Aqueous |
Significance and Applications
The production of sulphuric acid from sulphur dioxide, oxygen, and water is central to the Contact Process, the dominant industrial method for manufacturing H2SO4. Sulphuric acid has widespread applications, including:
- Fertilizer production: Used to make phosphate and ammonium fertilizers.
- Chemical manufacturing: A raw material for detergents, pigments, drugs, and explosives.
- Petroleum refining: Used in the purification of petroleum products.
- Metallurgy: Employed in the pickling of steel and non-ferrous metals.
This reaction also plays a role in environmental concerns, as sulphur dioxide emissions can contribute to acid rain when they react with atmospheric oxygen and water to form sulphuric acid droplets, harming ecosystems and infrastructure.
