Sulphuric acid is a strong, highly corrosive mineral acid composed of hydrogen, sulfur, and oxygen. It is one of the most widely used industrial chemicals and serves as a key raw material in the production of fertilizers, detergents, petroleum refining, pharmaceuticals, and many other products.
It is considered a “benchmark chemical” because the scale of its production often reflects a country’s industrial strength.
Chemical and Physical Properties
| Property | Value / Description |
|---|---|
| Chemical name | Sulphuric acid |
| Formula | H₂SO₄ |
| Molecular weight | 98.08 g/mol |
| CAS number | 7664-93-9 |
| Appearance | Colorless to slightly yellow, oily, viscous liquid |
| Odor | Odorless |
| Density | 1.84 g/cm³ (at 20°C, concentrated) |
| Melting point | 10°C |
| Boiling point | 337°C (with decomposition) |
| pH | < 1 (very strong acid) |
| Solubility | Completely miscible with water (highly exothermic reaction) |
| Viscosity | High; increases with concentration |
| Reactivity | Strong dehydrating and oxidizing agent; reacts violently with water and many organic compounds |
| Corrosion | Highly corrosive to metals, skin, and organic matter |
Important Safety Note
When diluting:
➡️ Always add acid to water (A → W), never water to acid.
This prevents splattering due to the exothermic reaction.
Applications & Uses
1. Fertilizer Industry (Largest Use)
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Production of phosphoric acid
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Used to manufacture phosphate fertilizers such as:
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DAP (diammonium phosphate)
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MAP (monoammonium phosphate)
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SSP (single superphosphate)
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2. Chemical Manufacturing
Used as a raw material to produce:
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Hydrochloric acid
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Nitric acid
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Synthetic detergents
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Dyes and pigments
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Pharmaceuticals
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Explosives
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Plastics (e.g., nylon precursors)
3. Petroleum Refining
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Used in alkylation processes
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Removes impurities from gasoline and diesel streams
4. Metal Processing
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Pickling of steel – removes rust and scale
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Cleaning metal surfaces before plating or galvanizing
5. Batteries
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Used as electrolyte in lead–acid batteries (car batteries)
6. Water Treatment
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pH control
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Coagulation enhancement
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Industrial wastewater treatment
7. Laboratory Use
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Dehydrating agent
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Catalyst for esterification and other organic reactions
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Digesting samples for chemical analysis
8. Cleaning & Industrial Maintenance
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Removal of rust
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Production of cleaning agents (controlled formulations)
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Not used in household cleaners due to its extreme corrosivity
Hazards & Safety Precautions
Sulphuric acid is extremely hazardous.
Major hazards
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Highly corrosive to skin, metals, and eyes
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Causes severe chemical burns
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Vapors are irritating and corrosive
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Strong exothermic reaction with water
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Reacts violently with organic materials (e.g., sugar, wood)
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Dehydrating and oxidizing agent
Safety precautions
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Wear acid-resistant gloves, face shield, goggles
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Use fume hood for handling concentrated acid
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Store in corrosion-resistant containers
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Keep away from heat, water, and reactive chemicals
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Neutralize spills with carbonate materials (e.g., sodium bicarbonate)
