Sulphuric Acid

Sulfuric acid (alternative spelling sulphuric acid), also known as vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with molecular formula H2SO4. It is a colorless, odorless, and syrupy liquid that is soluble in water, in a reaction that is highly exothermic.

Its corrosiveness can be mainly ascribed to its strong acidic nature, and, if at a high concentration, its dehydrating and oxidizing properties. It is also hygroscopic, readily absorbing water vapor from the air.Upon contact, sulfuric acid can cause severe chemical burns and even secondary thermal burns; it is very dangerous even at moderate concentrations.

Chemical formula: H2SO4

Molar mass: 98.079 g/mol

Appearance: Clear, colorless liquid

Odor: odorless

Density: 1.8302 g/cm3, liquid

Melting point: 10.31°C (50.56 °F; 283.46 K)

Boiling point 337°C (639 °F; 610 K) When sulfuric acid is above 300 °C (572 °F), it will decompose slowly

Solubility in water: miscible, exothermic

Vapor pressure: 0.001 mmHg (20 °C)

Acidity (pKa): −3, 1.99

Conjugate base: Hydrogen sulfate

Viscosity: 6.7 cP (20 °C)

Sulphuric Acid is used in chemical industry for production of detergents, synthetic resins, dyestuffs, pharmaceuticals, petroleum catalysts, insecticides and antifreeze, as well as in various processes such as oil well acidicizing, aluminium reduction, paper sizing, water treatment. About 6% of uses are related to pigments and include paints, enamels, printing inks, coated fabrics and paper, and the rest is dispersed into a multitude of applications such as production of explosives, cellophane, acetate and viscose textiles, lubricants, non-ferrous metals, and batteries.

Sulfuric acid is used in large quantities by the iron and steelmaking industry to remove oxidation, rust, and scaling from rolled sheet and billets prior to sale to the automobile and major appliances industry.[citation needed] Used acid is often recycled using a spent acid regeneration (SAR) plant. These plants combust spent acid[clarification needed] with natural gas, refinery gas, fuel oil or other fuel sources. This combustion process produces gaseous sulfur dioxide (SO2) and sulfur trioxide (SO3) which are then used to manufacture “new” sulfuric acid. SAR plants are common additions to metal smelting plants, oil refineries, and other industries where sulfuric acid is consumed in bulk, as operating a SAR plant is much cheaper than the recurring costs of spent acid disposal and new acid purchases.

Hydrogen peroxide (H2O2) can be added to sulfuric acid to produce piranha solution, a powerful but very toxic cleaning solution with which substrate surfaces can be cleaned. Piranha solution is typically used in the microelectronics industry, and also in laboratory settings to clean glassware.