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Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula H 2 SO 4. It is a colorless, odorless, and viscous liquid that is miscible with water. [7] Structure ...
The first and faster [citation needed] process is the removal of hydrogen and oxygen as units of water by the concentrated sulfuric acid. This occurs because hydration of concentrated sulfuric acid is strongly thermodynamically favorable, with a standard enthalpy of reaction of −880 kJ/mol.
The contact process is a method of producing sulfuric acid in the high concentrations needed for industrial processes. Platinum was originally used as the catalyst for this reaction; however, because it is susceptible to reacting with arsenic impurities in the sulfur feedstock, vanadium(V) oxide (V 2 O 5) has since been preferred.
Concentrated sulfuric acid is a strong dehydrating agent that can strip available water molecules and water components from sugar and organic tissue. [ 141 ] The burning of coal and/or petroleum by industry and power plants generates sulfur dioxide (SO 2 ) that reacts with atmospheric water and oxygen to produce sulfurous acid (H 2 SO 3 ). [ 142 ]
Subsequently, this sulphate ester is hydrolyzed to regenerate sulphuric acid and release ethanol: C 2 H 5-O-SO 3 H + H 2 O → H 2 SO 4 + C 2 H 5 OH. This two step route is called the "indirect process". In the "direct process," the acid protonates the alkene, and water reacts with this incipient carbocation to give the alcohol.
Water-reactive substances [1] are those that spontaneously undergo a chemical reaction with water, often noted as generating flammable gas. [2] Some are highly reducing in nature. [ 3 ] Notable examples include alkali metals , lithium through caesium , and alkaline earth metals , magnesium through barium .
Treatment of sulfur with hydrogen gives hydrogen sulfide.When dissolved in water, hydrogen sulfide is mildly acidic: [5] H 2 S ⇌ HS − + H +. Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide.
Hydrogen sulfide burns in oxygen with a blue flame to form sulfur dioxide (SO 2) and water: 2 H 2 S + 3 O 2 → 2 SO 2 + 2 H 2 O. If an excess of oxygen is present, sulfur trioxide (SO 3) is formed, which quickly hydrates to sulfuric acid: H 2 S + 2 O 2 → H 2 SO 4