Sulfuric Acid Uses

Sulfuric Acid, also called Hydrogen Sulfate, is a chemical substance with the formula H₂SW₄, widely used in industry and with a high experimental value. It's one of the Stronger acids, being a Diprotic acid when in solution.

History of Sulfuric Acid

The early alchemists knew Sulfuric Acid H₂SW_4. It was prepared by heating natural sulfates at a high temperature and dissolving Sulfur Trioxide SO₃ thus formed.

In the 15th century, Basilio Valentín obtained it by distilling Ferrous Sulfate with sand. The common name for Ferrous Sulfate, FeSO₄* 7H₂Or, it was "Iron vitriol", and the oleaginous product that was obtained from it was called "Vitriol Oil", name that is still used.

The first successful obtaining of Sulfuric Acid on an industrial scale was carried out in 1740 by Ward, in England. S Sulfur and Potassium Nitrate (nitro) were burned in a container suspended in a large glass globe partially filled with water. Then the glass chambers were replaced by lead ones, and in 1793 it was seen that Sulfur Dioxide was oxidized in the course of the process due to the influence of Nitrogen Oxides that were formed from Nitrate employee.

Little by little modifications were introduced in the method, tending to reduce the cost of production and to improve the quality of the product, and at the beginning of the XIX century the manufacture became keep going. The procedure, called "Lead Chamber Method", continues to be used today.

Physical Properties of Sulfuric Acid

Pure Hydrogen Sulfate is a colorless oily liquid, density 1.84 g / cm³ at 15 ° C. It freezes at 10.5 ° C, giving a colorless crystalline solid. When heated, it emits fumes, as it decomposes into water and sulfur trioxide, but the vapors contain a higher mole fraction of trioxide than water.

Consequently, the composition of the liquid decreases in H₂SW₄ and the temperature rises until a mixture of constant boiling point is formed, which boils at 338 ° C. Constant boiling point acid contains 98.33% H₂SW_4.

Characteristics and Chemical Properties of Sulfuric Acid

Heat of Dissolution

Sulfuric Acid mixes with water in all proportions. However, the preparation of diluted Sulfuric Acid must be carried out with care, because when mixing the Acid Concentrated with Water, a considerable amount of heat is given off, amounting to 17,750 calories when dissolved one mole of H₂SW₄ in Water.

For this reason, the concentrated acid must always be added to the water in small portions, stirring continuously, so that all the water and not a small part of it absorbs the heat developed; otherwise, this will be enough to convert the water into steam and spread the concentrated and hot acid in all directions.

Instability

When heated, Hydrogen Sulfate H₂SW₄ dissociates into Sulfur Trioxide, and Water:

H₂SW₄ -> SO₃ + H₂OR

At the boiling point, 338 ° C, it is 30% dissociated; at 420 ° C the dissociation is almost complete. When it is flashed red-hot, such as by dripping it onto red-hot iron, it completely decomposes into water, sulfur dioxide, and oxygen.

Dehydrating action

Sulfuric Acid H₂SW₄combines vigorously with water, giving a series of hydrates, of which the best known is the monohydrate H₂SW₄* H₂OR. This reaction with water is so pronounced that sulfuric acid not only removes water from the materials that contain it, but with It also frequently removes Hydrogen and Oxygen from the compounds, especially if they contain these elements in the same proportion as they will be in the water, H₂OR.

Thus, paper and wood, made up for the most part by cellulose, (C₆H₁₀OR₅) x and sugar (C₁₂H₂₂OR₁₁), they char in the presence of concentrated sulfuric acid, being released coal:

C₁₂H₂₂OR₁₁ -> 12C + 11H₂OR

This dehydrating action of sulfuric acid is used to dry out gases (that do not react with it), and to remove water in many chemical reactions, such as Nitration, when making dyes and explosives.

Oxidizing Action

Hot, concentrated Sulfuric Acid is an Oxidizer. Actively participates in REDOX reactions increasing the oxidation state of a susceptible element.

Examples of Uses of Sulfuric Acid

Sulfuric Acid H₂SW₄ it is used in large quantities in many industries. In times of war, the munitions industries consume it far above the current consumption, while other industries of a peaceful nature reduce it below normal.

1.- Fertilizers: Sulfuric Acid H₂SW₄ is used to produce Ammonium Sulfate (NH₄)₂SW₄ and Superphosphates.

2.- Oil refining: Sulfuric Acid H₂SW₄ It is used to remove impurities from various petroleum products, such as gasoline, kerosene (oil for lighting), solvents, etc.; otherwise, impurities discolor products, cause waxy deposits in liquid fuels and lubricants, and unpleasant odors in others.

3.- Chemical manufacturing: Sulfuric Acid H₂SW₄ It is used to make other acids, such as Hydrochloric and Nitric, and Sulfates of metals. It is also used in the manufacture of Sodium Carbonate Na₂CO₃ and Ethers.

4.- Manufacture of Dyes and Drugs: Sulfuric Acid H is used₂SW₄ to obtain products derived from coal tar, such as colorants, drugs and disinfectants.

5.- Steel Stripping: The surface of the steel is cleaned of rust by immersing it in a bath of Sulfuric Acid, before coating it with enamel, tin or zinc.

6.- Metallurgy: Certain metals are obtained by electrolysis of solutions of their sulfates. Others are purified by electrolysis, using the impure metal as the anode and Sulfuric Acid as the electrolyte, while the pure metal is deposited on the cathode.

7.- Paints and pigments: Many of the pigments used in paint are sulfates.

8.- Various applications: Sulfuric acid is used in the manufacture of fabrics, plastics, explosives, accumulators and other products.

9.- As a dehydrator: In organic Synthesis reactions, concentrated Sulfuric Acid is used to remove or assimilate the water molecules, so that they are not reintegrated into the process.

10.- As an Oxidizer: In chemical reactions, Sulfuric Acid is also used to modify the oxidation state of a participating element, from the reactants to the products.