Definition
Sulfuric acid (H₂SO₄) is a strong, mineral (inorganic) acid composed of hydrogen, sulfur, and oxygen. It is a colorless, oily liquid that is highly corrosive and hygroscopic.
Overview
Sulfuric acid is one of the most important industrial chemicals, employed in the production of fertilizers (particularly phosphates), petroleum refining, metal processing, chemical synthesis, and battery manufacturing. It is manufactured on a massive scale, with global annual production exceeding 200 million metric tonnes. The acid is also used in laboratory settings as a drying agent and a reagent for various acid–base and oxidation reactions.
Etymology/Origin
The name combines “sulfur,” derived from the Latin sulphur (itself from Greek theios “fiery”), with “acid,” from the Latin acidus meaning “sour” or “sharp.” The term “sulfuric acid” was first employed in the late 18th century to describe the aqueous solution of the compound produced by the oxidation of sulfur dioxide.
Characteristics
- Chemical formula: H₂SO₄
- Molecular weight: 98.079 g·mol⁻¹
- Physical state: Colorless, viscous liquid at room temperature; solidifies into white crystals below 10 °C.
- Density: 1.84 g·cm⁻³ (20 °C)
- Boiling point: 337 °C (decomposes in the vapor phase)
- Acidity: Strong acid; fully dissociates in water to produce hydronium ions (H₃O⁺) and sulfate ions (SO₄²⁻).
- Hygroscopicity: Absorbs water vapor from the atmosphere, forming dilute aqueous solutions.
- Reactivity: Reacts vigorously with water (exothermic dilution), metals (producing hydrogen gas and metal sulfates), organic compounds (often oxidizing them), and bases (forming salts).
- Corrosivity: Causes severe chemical burns on skin and damages many materials, including certain plastics and metals, unless specially resistant alloys are used.
Related Topics
- Acid–base chemistry – the behavior of strong acids and their conjugate bases.
- Fertilizer production – particularly the manufacture of ammonium sulfate and superphosphate fertilizers.
- Petroleum refining – use in alkylation and as a catalyst in various refining processes.
- Lead–acid batteries – sulfuric acid serves as the electrolyte in conventional automotive batteries.
- Industrial safety – protocols for handling, storage, and emergency response to sulfuric acid spills.
- Chemical synthesis – role as a dehydrating and sulfonating agent in organic synthesis.