Axit Sulfuric - H2SO4 5 - 98%

Physical properties:

Although 100% sulfuric acid can be produced, it will lose SO3 at the boiling point to give 98.3% acid. 98% acid is also more stable in storage, as it is the usual form of concentrated sulfuric acid. Different concentrations of sulfuric acid are used for different purposes. Some common concentrations are:

• 10%, dilute sulfuric acid for laboratory use.
• 33.5%, battery acid (used in lead-acid batteries)
• 62.18%, tank acid (lead) or for fertilizer production
• 77.67%, acid in the production tower or Glover acid.
• 98%, concentrated

There are also different grades of purity. Technical grade H2SO4 is impure and usually colored, but it is suitable for fertilizer production. Pure grades such as the US Pharmacopoeia (USP) grade are used in the manufacture of pharmaceuticals and dyes.

When high concentration SO3(gas) is added to sulfuric acid, H2S2O7 is produced. It is known as fuming sulfuric acid or oleum, or less commonly Nordhausen acid. The concentration of oleum is either expressed as %SO3 (referred to as %oleum) or as “%H2SO4 (the amount formed if H2O water has been added); The predominant concentrations were 40% oleum (109% H2SO4) and 65% oleum (114.6 % H2SO4). Pure H2S2O7 is in fact a solid with a melting point of 36 °C.

Chemical properties:

The hydration (hydration) reaction of sulfuric acid is a highly exothermic reaction. If water is added to concentrated sulfuric acid, it will boil and shoot out dangerously. Therefore, when diluting an acid, the acid must be added to the water, not the water to the acid. This phenomenon occurs because of the relative density of the two liquids, while water has a lower density than sulfuric acid, so it will tend to float to the top. This reaction is more precisely the reaction that produces hydronium ions, as follows:

H₂SO₄ + H₂O → H₃O⁺ + HSO₄^–.

Later:

HSO₄^– + H₂O → H₃O⁺ + SO₄^2-

Since the hydration of sulfuric acid is thermodynamically forward (H = 880 kJ/mol). Sulfuric acid is a very good water absorber, and it is used in the production of many types of dried fruit. The affinity of sulfuric acid for water is strong enough to extract hydrogen and oxygen atoms from their compounds; for example, the sugar glucose(C6H12O6) will be absorbed by concentrated sulfuric acid to produce elemental carbon and the acid solution will be slightly diluted: C6H12O6 → 6C + 6H2O.

As an acid, sulfuric acid reacts with most bases to produce the corresponding sulfate salt. For example, copper(II) sulfate, a familiar blue salt of copper used in electroplating and as a fungicide, is prepared by reacting copper(II) oxide with sulfuric acid:

CuO + H₂SO₄ → CuSO₄ + H₂O

Sulfuric acid can also be used to displace weaker acids from their salts, for example sodium acetate produces acetic acid:

H₂SO₄ + CH₃COONa → NaHSO₄ + CH₃COOH

Similarly, the reaction of sulfuric acid with potassium nitrate can be used to produce nitric acid, along with the formation of potassium bisulfate. With nitric acid itself, sulfuric acid reacts both as an acid and as a reducing agent, yielding nitronium NO2+ ions, which are important in nitrification reactions involving electrophilic aromatic ring substitution. death. This type of reaction, where protonation takes place on the oxygen atom, is important in many organic chemistry reactions, such as Fischer esterification and dehydration of alcohols.

Sulfuric acid reacts with most metals in a single substitution reaction to produce hydrogen gas and metal sulfate salts. Dilute H2SO4 acid reacts with iron, aluminum, zinc, manganese and nickel, but tin and copper require hot concentrated acids. Lead and tungsten are resistant to sulfuric acid corrosion. The iron reaction shown below is common to many metals, but the reaction with tin is unusual in that sulfur dioxide (sulfur dioxide) is produced rather than hydrogen.

Fe(r) + H₂SO₄(dd) → H₂(k) + FeSO₄(dd)

Sn(r) + 2 H₂SO₄(l) → SnSO₄ + 2 H₂O + SO₂

Lead hardly reacts with dilute H2SO4 but soluble in hot concentrated H2SO4 acid according to the following reaction:

Pb + 3H₂SO_4đđ → Pb(HSO₄)₂ + SO₂ + 2H₂O

Sulfuric acid is a very important commercial chemical, and indeed a country's sulfuric acid production is a good indicator of its industrial strength. The main use of sulfuric acid (60% of world production) is in the “wet method” of phosphoric acid production, which is used to produce phosphate fertilizers as well as sodium triphosphate for make laundry detergent. In this method phosphate rock is used, and more than 100 million tons are produced annually. The raw material indicated below is fluoro-apatite, although the exact composition can vary widely. It is treated with 93% sulfuric acid to produce calcium sulfate, hydrogen fluoride (HF) and phosphoric acid. HF is eliminated in the form of fluorosilicic acid. The overview process can be represented as follows:

Ca₅F(PO₄)₃ + 5 H₂SO₄ + 10 H₂O → 5 CaSO₄·2 H₂O + HF + 3 H₃PO₄

Sulfate fertilizers such as ammonium sulfate are produced from sulfuric acid, although in less yield than phosphates.

Another important application of sulfuric acid is to produce aluminum sulfate, also known as paper alum. It can react with a small amount of soap on the pulp fibers to produce gelatin aluminum carboxylate, which helps to solidify the pulp fibers into the hard surface of the paper. It is also used to produce aluminum hydroxide, which is used in water treatment plants to filter impurities, as well as to improve the taste of water. Aluminum sulfate is produced from the reaction of bauxite with sulfuric acid:

Al₂O₃ + 3 H₂SO₄ → Al₂(SO₄)₃ + 3 H₂O

Sulfuric acid is also used for other purposes in the chemical industry. For example, it is a common acid catalyst for the conversion of cyclohexanoneoxime to caprolactam, which is used to manufacture nylon. It is also used to produce hydrochloric acid from table salt by the Mannheim process. Much of H2SO4 is used in the petrochemical industry to refine petroleum, for example as a catalyst for the reaction of isobutane with isobutylene to produce isooctane, which increases the octane number of gasoline. Sulfuric acid is also important for the manufacture of dyes.

A mixture of sulfuric acid and water is used as an electrolyte in a variety of lead-acid batteries where it participates in a reversible reaction for lead (Pb) and lead dioxide (PbO2) to be converted to lead. II) sulfate. Sulfuric acid is also a basic ingredient in some drain cleaners, used to clean obstructions containing paper, rags, and other materials that are not easily cleaned with caustic soda solutions. .