The chemical properties of sulfuric acid are:
1. Interaction with metals:
Dilute acid dissolves only those metals that are to the left of hydrogen in the voltage series, for example H 2 +1 SO 4 + Zn 0 = H 2 O + Zn +2 SO 4;
The oxidizing properties of sulfuric acid are great. When interacting with various metals (except Pt, Au), it can be reduced to H 2 S -2, S +4 O 2 or S 0, for example:
2H 2 +6 SO 4 + 2Ag 0 = S +4 O 2 + Ag 2 +1 SO 4 + 2H 2 O;
5H 2 +6 SO 4 +8Na 0 = H 2 S -2 + 4Na 2 +1 SO 4 + 4H 2 O;
2. Concentrated acid H 2 S +6 O 4 also reacts (when heated) with some non-metals, turning into sulfur compounds with a lower oxidation state, for example:
2H 2 S +6 O 4 + C 0 = 2S +4 O 2 + C +4 O 2 + 2H 2 O;
2H 2 S +6 O 4 + S 0 = 3S +4 O 2 + 2H 2 O;
5H 2 S +6 O 4 + 2P 0 = 2H 3 P +5 O 4 + 5S +4 O 2 + 2H 2 O;
3. With basic oxides:
H 2 SO 4 + CuO = CuSO 4 + H 2 O;
4. With hydroxides:
Cu(OH) 2 + H 2 SO 4 = CuSO 4 + 2H 2 O;
2NaOH + H 2 SO 4 = Na 2 SO 4 + 2H 2 O;
5. Interaction with salts during metabolic reactions:
H 2 SO 4 + BaCl 2 = 2HCl + BaSO 4;
The formation of BaSO 4 (a white precipitate insoluble in acids) is used to determine this acid and soluble sulfates.
The idea that the atom of an element has the ability to “saturate” was expressed in 1853 by E. Frankland when considering the constitution of organometallic compounds. Developing this idea, in 1854 Kekule first expressed the idea of “bibasicity”, or “diatomicity” (later he began to use the term “valency”) of sulfur and oxygen, and in 1857 he divided all elements into one-, two- and tribasic; Kekule (simultaneously with the German chemist G. Kolbe) identified carbon as a tetraatomic element. In 1858, Kekule (at the same time as the Scottish chemist A. Cooper) pointed out the ability of carbon atoms to form chains when their “affinity units” are saturated. This mechanical doctrine of the connection of atoms in a chain to form molecules formed the basis of the theory of chemical structure.
In 1865, Kekule suggested that the benzene molecule has the shape of a regular hexagon formed by six carbon atoms to which six hydrogen atoms are bonded. Combining the idea of the formation of chains with the doctrine of the existence of multiple bonds, he came to the idea of alternating single and double bonds in the benzene ring (similar structural formulas were proposed shortly before by I. Loschmidt). Despite the fact that this theory immediately encountered objections, it quickly took root in science and practice.
Kekule's concept opened the way to establishing the structure of many cyclic (aromatic) compounds. To explain the inability of benzene to add hydrogen halides, Kekulé in 1872 put forward an oscillatory hypothesis, according to which single and double bonds in benzene constantly change places. In 1867, Kekule published a paper on the spatial arrangement of atoms in a molecule, where he indicated that the bonds of a carbon atom may not be in the same plane.
Kekule was president of the German Chemical Society for several years. He was one of the organizers of the International Congress of Chemists in Karlsruhe (1860). Kekule's pedagogical activity was very fruitful. He is the author of the widely acclaimed Textbook of Organic Chemistry (1859-1861). A number of Kekule's students became outstanding chemists; Among them we can especially note L. Meyer, J. Van't Hoff, A. Bayer and E. Fischer.
BUTLEROV, Alexander Mikhailovich
Russian chemist Alexander Mikhailovich Butlerov was born in Chistopol, Kazan province, into the family of a landowner, a retired officer. Having lost his mother early, Butlerov was brought up in one of the private boarding schools in Kazan, then studied at the Kazan gymnasium. At the age of sixteen, he entered the physics and mathematics department of Kazan University, which at that time was the center of natural science research in Russia.
In the first years of his student life, Butlerov was interested in botany and zoology, but then, under the influence of lectures by K. K. Klaus and N. N. Zinin, he became interested in chemistry and decided to devote himself to this science. In 1849, Butlerov graduated from the university and, at the suggestion of Klaus, was retained at the department as a teacher. In 1851 he defended his master's thesis “On the oxidation of organic compounds”, and in 1854 - his doctoral thesis “On essential oils”. In 1854 Butlerov became extraordinary, and in 1857 - ordinary professor of chemistry at Kazan University.
During a trip abroad in 1857-1858. Butlerov met many leading chemists in Europe and participated in meetings of the newly organized Paris Chemical Society. In the laboratory of S. A. Wurtz, Butlerov began a series of experimental studies, which served as the basis for the theory of chemical structure. He formulated its main provisions in the report “On the Chemical Structure of Matter,” read at the Congress of German Naturalists and Doctors in Speyer (September 1861).
The foundations of this theory are formulated as follows: 1) “Assuming that each chemical atom is characterized by only a certain and limited amount of chemical force (affinity) with which it takes part in the formation of a body, I would call this chemical bond, or method of mutual connection, chemical structure atoms in a complex body"; 2) “... the chemical nature of a complex particle is determined by the nature of its elementary constituent parts, their quantity and chemical structure.”
All other provisions of the classical theory of chemical structure are directly or indirectly related to these postulates. Butlerov outlines the path for determining the chemical structure and formulates the rules that can be followed in this case. He gives preference to synthetic reactions carried out under conditions where the radicals involved in them retain their chemical structure.
Leaving open the question of the preferred form of formulas for chemical structure, Butlerov spoke about their meaning: “... when the general laws of the dependence of the chemical properties of bodies on their chemical structure become known, then such a formula will be an expression of all these properties.” At the same time, Butlerov was convinced that structural formulas cannot be simply a conventional image of molecules, but must reflect their real structure. He emphasized that each molecule has a very specific structure and cannot combine several such structures.
Of great importance for the development of the theory of chemical structure was its experimental confirmation in the works of both Butlerov himself and his school. Butlerov foresaw and then proved the existence of positional and skeletal isomerism. Having obtained tertiary butyl alcohol, he was able to decipher its structure and proved (together with his students) the presence of isomers. In 1864, Butlerov predicted the existence of two butanes and three pentanes, and later isobutylene.
He also suggested the existence of four valeric acids; the structure of the first three was determined in 1871 by E. Erlenmeyer, and the fourth was obtained by Butlerov himself in 1872. In order to carry the ideas of the theory of chemical structure through all organic chemistry, Butlerov published in 1864-1866. in Kazan, the book “Introduction to the complete study of organic chemistry”, 2nd ed. which was published already in 1867-1868. in German.
In 1868, on the recommendation of D.I. Mendeleev, Butlerov was elected an ordinary professor at St. Petersburg University, where he worked until the end of his life. In 1870 he became an extraordinary, and in 1874 - an ordinary academician of the St. Petersburg Academy of Sciences. From 1878 to 1882 he was President and Chairman of the Chemistry Department of the Russian Physical-Chemical Society.
Butlerov's teaching career lasted 35 years and took place in three higher educational institutions: Kazan, St. Petersburg universities and the Higher Women's Courses (he took part in their organization in 1878). Many of his students worked under the leadership of Butlerov, among whom can be named V.V. Markovnikov, F. M. Flavitsky, A. M. Zaitsev (in Kazan), A. E. Favorsky, I. L. Kondakov (in St. Petersburg). Butlerov became the founder of the famous Kazan (“Butlerov”) school of organic chemists. Butlerov also gave many popular lectures, mainly on chemical and technical topics.
In addition to chemistry, Butlerov paid a lot of attention to practical issues of agriculture, gardening, beekeeping, and later also to tea cultivation in the Caucasus. Since the late 1860s. Butlerov was actively interested in spiritualism and mediumship, to which he devoted several articles; This passion of Butlerov and his attempts to give spiritualism a scientific basis became the reason for his polemic with Mendeleev. Butlerov died in the village. Butlerovka of the Kazan province, before the final recognition of his theory. The two most significant Russian chemists - D.I. Mendeleev and N.A. Menshutkin - only ten years after Butlerov's death recognized the validity of the theory of chemical structure.
Benzene trimerization reaction
OVRs are specially highlighted in color in the article. Pay special attention to them. These equations may appear on the Unified State Exam.
Dilute sulfuric acid behaves like other acids, hiding its oxidative capabilities:
And one more thing to remember about dilute sulfuric acid: she does not react with lead. A piece of lead thrown into dilute H2SO4 becomes covered with a layer of insoluble (see solubility table) lead sulfate and the reaction immediately stops.
Oxidizing properties of sulfuric acid
– heavy oily liquid, non-volatile, tasteless and odorless
Due to sulfur in the oxidation state +6 (higher), sulfuric acid acquires strong oxidizing properties.
Rule for task 24 (old A24) when preparing sulfuric acid solutions You should never pour water into it. Concentrated sulfuric acid should be poured into water in a thin stream, stirring constantly.
Reaction of concentrated sulfuric acid with metals
These reactions are strictly standardized and follow the scheme:
H2SO4(conc.) + metal → metal sulfate + H2O + reduced sulfur product.
There are two nuances:
1) Aluminum, iron And chromium They do not react with H2SO4 (conc.) under normal conditions due to passivation. Needs to be heated.
2) C platinum And gold H2SO4 (conc) does not react at all.
Sulfur V concentrated sulfuric acid- oxidizer
- This means that it will recover itself;
- the degree of oxidation to which sulfur is reduced depends on the metal.
Let's consider sulfur oxidation state diagram:
- Before -2 sulfur can only be reduced by very active metals - in a series of voltages up to and including aluminum.
The reactions will go like this:
8Li+5H 2 SO 4( conc. .) → 4Li 2 SO 4 + 4H 2 O+H 2 S
4Mg + 5H 2 SO 4( conc. .) → 4MgSO 4 + 4H 2 O+H 2 S
8Al + 15H 2 SO 4( conc. .) (t)→ 4Al 2 (SO 4 ) 3 +12H 2 O+3H 2 S
- upon interaction of H2SO4 (conc) with metals in a series of voltages after aluminum, but before iron, that is, with metals with average activity, sulfur is reduced to 0 :
3Mn + 4H 2 SO 4( conc. .) → 3MnSO 4 + 4H 2 O+S↓
2Cr + 4H 2 SO 4( conc. .) (t)→Cr 2 (SO 4 ) 3 + 4H 2 O+S↓
3Zn + 4H 2 SO 4( conc. .) → 3ZnSO 4 + 4H 2 O+S↓
- all other metals starting with hardware in a number of voltages (including those after hydrogen, except for gold and platinum, of course), they can only reduce sulfur to +4. Since these are low-active metals:
2 Fe + 6 H 2 SO 4(conc.) ( t)→ Fe 2 ( SO 4 ) 3 + 6 H 2 O + 3 SO 2
(note that iron oxidizes to +3, the highest possible oxidation state, since it is a strong oxidizing agent)
Cu+2H 2 SO 4( conc. .) → CuSO 4 + 2H 2 O+SO 2
2Ag + 2H 2 SO 4( conc. .) → Ag 2 SO 4 + 2H 2 O+SO 2
Of course, everything is relative. The depth of recovery will depend on many factors: acid concentration (90%, 80%, 60%), temperature, etc. Therefore, it is impossible to predict products completely accurately. The above table also has its own approximate percentage, but you can use it. It is also necessary to remember that in the Unified State Examination, when the product of reduced sulfur is not indicated and the metal is not particularly active, then, most likely, the compilers mean SO 2. You need to look at the situation and look for clues in the conditions.
SO 2 - this is generally a common product of ORR with the participation of conc. sulfuric acid.
H2SO4 (conc) oxidizes some nonmetals(which exhibit reducing properties), as a rule, to a maximum - the highest degree of oxidation (an oxide of this non-metal is formed). In this case, sulfur is also reduced to SO 2:
C+2H 2 SO 4( conc. .) → CO 2 + 2H 2 O+2SO 2
2P+5H 2 SO 4( conc. .) → P 2 O 5 +5H 2 O+5SO 2
Freshly formed phosphorus oxide (V) reacts with water to produce orthophosphoric acid. Therefore, the reaction is recorded immediately:
2P+5H 2 SO 4( conc. ) → 2H 3 P.O. 4 + 2H 2 O+5SO 2
The same thing with boron, it turns into orthoboric acid:
2B+3H 2 SO 4( conc. ) → 2H 3 B.O. 3 +3SO 2
The interaction of sulfur with an oxidation state of +6 (in sulfuric acid) with “other” sulfur (located in a different compound) is very interesting. Within the framework of the Unified State Examination, the interaction of H2SO4 (conc) is considered with sulfur (a simple substance) and hydrogen sulfide.
Let's start with interaction sulfur (a simple substance) with concentrated sulfuric acid. In a simple substance the oxidation state is 0, in an acid it is +6. In this ORR, sulfur +6 will oxidize sulfur 0. Let's look at the diagram of the oxidation states of sulfur:
Sulfur 0 will oxidize, and sulfur +6 will be reduced, that is, lower the oxidation state. Sulfur dioxide will be released:
2 H 2 SO 4(conc.) + S → 3 SO 2 + 2 H 2 O
But in the case of hydrogen sulfide:
Both sulfur (a simple substance) and sulfur dioxide are formed:
H 2 SO 4( conc. .) +H 2 S → S↓ + SO 2 + 2H 2 O
This principle can often help in identifying an ORR product where the oxidizing agent and the reducing agent are the same element, in different oxidation states. The oxidizing agent and the reducing agent “meet each other halfway” according to the oxidation state diagram.
H2SO4 (conc), one way or another, interacts with halides. Only here you need to understand that fluorine and chlorine are “themselves with a mustache” and ORR does not occur with fluorides and chlorides, undergoes a conventional ion exchange process during which hydrogen halide gas is formed:
CaCl 2 + H 2 SO 4 (conc.) → CaSO 4 + 2HCl
CaF 2 + H 2 SO 4 (conc.) → CaSO 4 + 2HF
But the halogens in the composition of bromides and iodides (as well as in the composition of the corresponding hydrogen halides) are oxidized to free halogens. Only sulfur is reduced in different ways: iodide is a stronger reducing agent than bromide. Therefore, iodide reduces sulfur to hydrogen sulfide, and bromide to sulfur dioxide:
2H 2 SO 4( conc. .) + 2NaBr → Na 2 SO 4 + 2H 2 O+SO 2 +Br 2
H 2 SO 4( conc. .) + 2HBr → 2H 2 O+SO 2 +Br 2
5H 2 SO 4( conc. .) + 8NaI → 4Na 2 SO 4 + 4H 2 O+H 2 S+4I 2 ↓
H 2 SO 4( conc. .) + 8HI → 4H 2 O+H 2 S+4I 2 ↓
Hydrogen chloride and hydrogen fluoride (as well as their salts) are resistant to the oxidizing action of H2SO4 (conc).
And finally, the last thing: this is unique for concentrated sulfuric acid, no one else can do this. She has water-removing property.
This allows concentrated sulfuric acid to be used in a variety of ways:
First, drying of substances. Concentrated sulfuric acid removes water from the substance and it “becomes dry.”
Secondly, a catalyst in reactions in which water is eliminated (for example, dehydration and esterification):
H 3 C–COOH + HO–CH 3 (H 2 SO 4 (conc.)) → H 3 C–C(O)–O–CH 3 + H 2 O
H 3 C–CH 2 –OH (H 2 SO 4 (conc.)) → H 2 C =CH 2 + H 2 O
Concentrated acid, safety precautions when working.
SULFURIC ACID. PHYSICAL AND CHEMICAL PROPERTIES.
Physical properties: Anhydrous sulfuric acid is a colorless oily liquid that crystallizes at 10.5 0 C. It is miscible with water in any ratio. When dissolved in water, a large amount is released
warmth. In this case, sulfuric acid hydrates are formed.
Because the dissolution of H 2 SO 4 in water is accompanied by the release of a large amount of heat; this operation must be carried out with great care. To avoid splashing of the heated surface layer of the solution, sulfuric acid should be poured into the water.
Concentrated sulfuric acid vigorously absorbs moisture and is therefore used to dry gases.
CHEMICAL PROPERTIES OF SULFURIC ACID.
It is a dibasic acid.
Structural formula:
Concentrated sulfuric acid - energetic oxidizing agent :
1. When heated, it oxidizes most metals, including copper, silver, and mercury. Depending on the activity of the metal, the reduction products can be: S 0 , SO 2 , H 2 S, but more often until SO2.
For example: When interacting with copper and other low-active metals upon heating, it forms SO 2.
Cu + 2 H 2 SO 4 = CuSO 4 + SO 2 + H 2 O
Reductant oxidizer
Cu 0 - 2ē - Cu +2 1 ok, I'm glad
SO 4 2- + 4H - +2ē - SO 2 0 +2H 2 O 1 Ave. Sunday ok
In the cold, concentrated sulfuric acid (above 93%) does not interact with active metals such as aluminum, iron, and chromium.
This phenomenon is explained by the passivation of metals. This feature of sulfuric acid is widely used for transporting the latter in iron containers.
2. When boiled, it oxidizes non-metals such as sulfur and carbon:
S + 2 H 2 SO 4 = 3 SO 2 +2 H 2 O
C + 2 H 2 SO 4 = CO 2 + 2 SO 2 + 2 H 2 O
3. Water-removing effect (charring).
PROPERTIES OF DILUTATE SULFURIC ACID.
1. Changes the color of the indicator.
2. Interacts with basic and amphoteric oxides:
Na 2 O + H 2 SO 4 = Na 2 SO 4 + H 2 O
ZnO + H 2 SO 4 = ZnSO 4 + H 2 O
3. With bases (neutralization reaction):
H 2 SO 4 + 2KOH = K 2 SO 4 + H 2 O
3H 2 SO 4 + 2 Al(OH) 3 = Al 2 (SO 4) 3 + 6 H 2 O
4. With salts:
H 2 SO 4 + Ba(NO 3) 2 = BaSO 4 ↓+ 2 HNO 3
Conclusions:
1.Anhydrous sulfuric acid is a colorless oily liquid that crystallizes at 10.5 0 C. It can be mixed with water in any proportion.
2. Because the dissolution of H 2 SO 4 in water is accompanied by the release of a large amount of heat; this operation must be carried out with great care. To avoid splashing of the heated surface layer of the solution, sulfuric acid should be poured into the water.
3. Concentrated sulfuric acid vigorously absorbs moisture and is therefore used for drying gases.
4.Sulfuric acid is a dibasic acid.
5. Concentrated sulfuric acid - energetic oxidizing agent .
· When heated, it oxidizes most metals, including copper, silver, and mercury. Depending on the activity of the metal, the reduction products can be: S 0 , SO 2 , H 2 S, but more often until SO2.
· .In the cold, concentrated sulfuric acid (above 93%) does not interact with active metals such as aluminum, iron, chromium.
· When boiled, it oxidizes non-metals such as sulfur and carbon.
· Water-removing action (charring).
6. PROPERTIES OF DILUTATE SULFURIC ACID.
· Changes the color of the indicator.
· Interacts with:
· with basic and amphoteric oxides.
· With bases (neutralization reaction).
· With salts.
Sulfates. Qualitative reaction to sulfate ion
The reagent for sulfate ion is barium chloride.
Barium chloride BaCl2 precipitates from dilute solutions of sulfates a white crystalline, insoluble precipitate of barium sulfate:
BaCl 2 + Na 2 SO 4 = BaSO 4 ↓ + 2 NaCl
Ba 2+ + SO 4 2- = BaSO 4 ↓
pharmacopoeial reaction.
Technique: to 2 drops of sodium sulfate solution Na2SO4 add barium chloride solution BaCl2 and observe the precipitation.
Conclusions:
1. The reagent for sulfate ion is barium chloride.
2.Barium chloride BaCl2 Precipitates a white, crystalline, insoluble precipitate of barium sulfate from dilute solutions of sulfates.
Any acid is a complex substance whose molecule contains one or more hydrogen atoms and an acid residue.
The formula of sulfuric acid is H2SO4. Consequently, the sulfuric acid molecule contains two hydrogen atoms and the acidic residue SO4.
Sulfuric acid is formed when sulfur oxide reacts with water
SO3+H2O -> H2SO4
Pure 100% sulfuric acid (monohydrate) is a heavy liquid, viscous like oil, colorless and odorless, with a sour “copper” taste. Already at a temperature of +10 ° C it hardens and turns into a crystalline mass.
Concentrated sulfuric acid contains approximately 95% H2 SO4. And it hardens at temperatures below –20°C.
Interaction with water
Sulfuric acid dissolves well in water, mixing with it in any proportion. This releases a large amount of heat.
Sulfuric acid can absorb water vapor from the air. This property is used in industry for drying gases. The gases are dried by passing them through special containers with sulfuric acid. Of course, this method can only be used for those gases that do not react with it.
It is known that when sulfuric acid comes into contact with many organic substances, especially carbohydrates, these substances become charred. The fact is that carbohydrates, like water, contain both hydrogen and oxygen. Sulfuric acid takes these elements away from them. What remains is coal.
In an aqueous solution of H2SO4, the indicators litmus and methyl orange turn red, which indicates that this solution has a sour taste.
Interaction with metals
Like any other acid, sulfuric acid is capable of replacing hydrogen atoms with metal atoms in its molecule. It interacts with almost all metals.
Diluted sulfuric acid reacts with metals like an ordinary acid. As a result of the reaction, a salt with an acidic residue SO4 and hydrogen is formed.
Zn + H2SO4 = ZnSO4 + H2
A concentrated sulfuric acid is a very strong oxidizing agent. It oxidizes all metals, regardless of their position in the voltage series. And when reacting with metals, it itself is reduced to SO2. Hydrogen is not released.
Сu + 2 H2SO4 (conc) = CuSO4 + SO2 + 2H2O
Zn + 2 H2SO4 (conc) = ZnSO4 + SO2 + 2H2O
But gold, iron, aluminum, and platinum group metals do not oxidize in sulfuric acid. Therefore, sulfuric acid is transported in steel tanks.
The sulfuric acid salts that are obtained as a result of such reactions are called sulfates. They are colorless and easily crystallize. Some of them are highly soluble in water. Only CaSO4 and PbSO4 are slightly soluble. BaSO4 is almost insoluble in water.
Interaction with bases
The reaction between acids and bases is called neutralization reaction. As a result of the neutralization reaction of sulfuric acid, a salt containing the acid residue SO4 and water H2O are formed.
Examples of sulfuric acid neutralization reactions:
H2SO4 + 2 NaOH = Na2SO4 + 2 H2O
H2SO4 + CaOH = CaSO4 + 2 H2O
Sulfuric acid reacts with neutralization with both soluble and insoluble bases.
Since the sulfuric acid molecule has two hydrogen atoms, and two bases are required to neutralize it, it is classified as a dibasic acid.
Interaction with basic oxides
From the school chemistry course we know that oxides are complex substances that contain two chemical elements, one of which is oxygen in the oxidation state -2. Basic oxides are called oxides of 1, 2 and some 3 valence metals. Examples of basic oxides: Li2O, Na2O, CuO, Ag2O, MgO, CaO, FeO, NiO.
Sulfuric acid reacts with basic oxides in a neutralization reaction. As a result of this reaction, as in the reaction with bases, salt and water are formed. The salt contains the acidic residue SO4.
CuO + H2SO4 = CuSO4 + H2O
Interaction with salts
Sulfuric acid reacts with salts of weaker or volatile acids, displacing these acids from them. As a result of this reaction, a salt with an acidic residue SO4 and an acid are formed
H2SO4+BaCl2=BaSO4+2HCl
Application of sulfuric acid and its compounds
Barium porridge BaSO4 is capable of blocking X-rays. Filling the hollow organs of the human body with it, radiologists examine them.
In medicine and construction, natural gypsum CaSO4 * 2H2O and calcium sulfate crystalline hydrate are widely used. Glauber's salt Na2SO4 * 10H2O is used in medicine and veterinary medicine, in the chemical industry - for the production of soda and glass. Copper sulfate CuSO4 * 5H2O is known to gardeners and agronomists, who use it to combat pests and plant diseases.
Sulfuric acid is widely used in various industries: chemical, metalworking, oil, textile, leather and others.
In technology, sulfuric acid is called its mixture with both water and sulfuric anhydride SO3. If the molar ratio of SO3:H2O< 1, то это водный раствор серной кислоты, если >1 - solution of SO3 in sulfuric acid (oleum).
- 1 Title
- 2 Physical and physico-chemical properties
- 2.1 Oleum
- 3 Chemical properties
- 4 Application
- 5 Toxic effect
- 6 Historical information
- 7 Additional information
- 8 Preparation of sulfuric acid
- 8.1 First method
- 8.2 Second method
- 9 Standards
- 10 Notes
- 11 Literature
- 12 Links
Name
In the 18th-19th centuries, sulfur for gunpowder was produced from sulfur pyrite (pyrite) in vitriol factories. Sulfuric acid at that time was called “oil of vitriol” (as a rule, it was a crystalline hydrate, with a consistency reminiscent of oil), obviously hence the origin of the name of its salts (or rather, crystalline hydrates) - vitriol.
Physical and physico-chemical properties
Very strong acid, at 18°C pKa (1) = −2.8, pKa (2) = 1.92 (K₂ 1.2 10−2); bond lengths in the molecule S=O 0.143 nm, S-OH 0.154 nm, HOSOH angle 104°, OSO 119°; boils, forming an azeotropic mixture (98.3% H2SO4 and 1.7% H2O with a boiling point of 338.8 ° C). Sulfuric acid corresponding to 100% H2SO4 content has the following composition (%): H2SO4 99.5, HSO4− - 0.18, H3SO4+ - 0.14, H3O+ - 0.09, H2S2O7 - 0.04, HS2O7⁻ - 0.05. Miscible with water and SO3, in all proportions. In aqueous solutions, sulfuric acid almost completely dissociates into H3O+, HSO3+, and 2HSO₄−. Forms H2SO4 nH2O hydrates, where n = 1, 2, 3, 4 and 6.5.
Oleum
Main article: OleumSolutions of sulfuric anhydride SO3 in sulfuric acid are called oleum, they form two compounds H2SO4 SO3 and H2SO4 2SO3.
Oleum also contains pyrosulfuric acids, obtained by the reactions:
The boiling point of aqueous solutions of sulfuric acid increases with increasing its concentration and reaches a maximum at a content of 98.3% H2SO4.
| Content % by weight | Density at 20 ℃, g/cm³ | Melting point, ℃ | Boiling point, ℃ | |
|---|---|---|---|---|
| H2SO4 | SO3 (free) | |||
| 10 | - | 1,0661 | −5,5 | 102,0 |
| 20 | - | 1,1394 | −19,0 | 104,4 |
| 40 | - | 1,3028 | −65,2 | 113,9 |
| 60 | - | 1,4983 | −25,8 | 141,8 |
| 80 | - | 1,7272 | −3,0 | 210,2 |
| 98 | - | 1,8365 | 0,1 | 332,4 |
| 100 | - | 1,8305 | 10,4 | 296,2 |
| 104,5 | 20 | 1,8968 | −11,0 | 166,6 |
| 109 | 40 | 1,9611 | 33,3 | 100,6 |
| 113,5 | 60 | 2,0012 | 7,1 | 69,8 |
| 118,0 | 80 | 1,9947 | 16,9 | 55,0 |
| 122,5 | 100 | 1,9203 | 16,8 | 44,7 |
The boiling point of oleum decreases with increasing SO3 content. As the concentration of aqueous solutions of sulfuric acid increases, the total vapor pressure above the solutions decreases and reaches a minimum at a content of 98.3% H2SO4. As the concentration of SO3 in oleum increases, the total vapor pressure above it increases. The vapor pressure over aqueous solutions of sulfuric acid and oleum can be calculated using the equation:
the values of the coefficients A and depend on the concentration of sulfuric acid. Vapor over aqueous solutions of sulfuric acid consists of a mixture of water vapor, H2SO4 and SO3, and the composition of the vapor differs from the composition of the liquid at all concentrations of sulfuric acid, except for the corresponding azeotropic mixture.
With increasing temperature, dissociation increases:
Equation for the temperature dependence of the equilibrium constant:
At normal pressure, degree of dissociation: 10⁻⁵ (373 K), 2.5 (473 K), 27.1 (573 K), 69.1 (673 K).
The density of 100% sulfuric acid can be determined by the equation:
With increasing concentration of sulfuric acid solutions, their heat capacity decreases and reaches a minimum for 100% sulfuric acid; the heat capacity of oleum increases with increasing SO3 content.
With increasing concentration and decreasing temperature, thermal conductivity λ decreases:
where C is the concentration of sulfuric acid, in%.
Oleum H2SO4·SO3 has the maximum viscosity; with increasing temperature, η decreases. The electrical resistance of sulfuric acid is minimum at concentrations of SO3 and 92% H2SO4 and maximum at concentrations of 84 and 99.8% H2SO4. For oleum, the minimum ρ is at a concentration of 10% SO3. With increasing temperature, ρ of sulfuric acid increases. Dielectric constant of 100% sulfuric acid 101 (298.15 K), 122 (281.15 K); cryoscopic constant 6.12, ebullioscopic constant 5.33; the diffusion coefficient of sulfuric acid vapor in air varies depending on temperature; D = 1.67·10⁻⁵T3/2 cm²/s.
Chemical properties
Sulfuric acid in concentrated form when heated is a fairly strong oxidizing agent; oxidizes HI and partially HBr to free halogens, carbon to CO2, sulfur to SO2, oxidizes many metals (Cu, Hg, with the exception of gold and platinum). In this case, concentrated sulfuric acid is reduced to SO2, for example:
The most powerful reducing agents reduce concentrated sulfuric acid to S and H2S. Concentrated sulfuric acid absorbs water vapor, so it is used to dry gases, liquids and solids, for example in desiccators. However, concentrated H2SO4 is partially reduced by hydrogen, which is why it cannot be used for drying. By splitting water from organic compounds and leaving behind black carbon (charcoal), concentrated sulfuric acid leads to charring of wood, sugar and other substances.
Dilute H2SO4 interacts with all metals located in the electrochemical voltage series to the left of hydrogen with its release, for example:
The oxidizing properties of dilute H2SO4 are uncharacteristic. Sulfuric acid forms two series of salts: medium - sulfates and acidic - hydrosulfates, as well as esters. Peroxomonosulfuric acid (or Caro acid) H2SO5 and peroxodisulfuric acid H2S2O8 are known.
Sulfuric acid also reacts with basic oxides, forming sulfate and water:
In metalworking plants, a solution of sulfuric acid is used to remove a layer of metal oxide from the surface of metal products that are subjected to high heat during the manufacturing process. Thus, iron oxide is removed from the surface of sheet iron by the action of a heated solution of sulfuric acid:
A qualitative reaction to sulfuric acid and its soluble salts is their interaction with soluble barium salts, which results in the formation of a white precipitate of barium sulfate, insoluble in water and acids, for example:
Application
Sulfuric acid is used:
- in ore processing, especially in the extraction of rare elements, incl. uranium, iridium, zirconium, osmium, etc.;
- in the production of mineral fertilizers;
- as an electrolyte in lead batteries;
- for obtaining various mineral acids and salts;
- in the production of chemical fibers, dyes, smoke-forming and explosives;
- in the oil, metalworking, textile, leather and other industries;
- in the food industry - registered as a food additive E513(emulsifier);
- in industrial organic synthesis in reactions:
- dehydration (production of diethyl ether, esters);
- hydration (ethanol from ethylene);
- sulfonation (synthetic detergents and intermediates in the production of dyes);
- alkylation (production of isooctane, polyethylene glycol, caprolactam), etc.
- For the restoration of resins in filters in the production of distilled water.
World production of sulfuric acid is approx. 160 million tons per year. The largest consumer of sulfuric acid is the production of mineral fertilizers. P₂O₅ phosphorus fertilizers consume 2.2-3.4 times more mass of sulfuric acid, and (NH₄)₂SO₄ sulfuric acid consumes 75% of the mass of consumed (NH₄)₂SO₄. Therefore, they tend to build sulfuric acid plants in conjunction with factories for the production of mineral fertilizers.
Toxic effect
Sulfuric acid and oleum are very corrosive substances. They affect the skin, mucous membranes, and respiratory tract (cause chemical burns). When inhaling the vapors of these substances, they cause difficulty breathing, coughing, and often laryngitis, tracheitis, bronchitis, etc. The maximum permissible concentration of sulfuric acid aerosol in the air of the working area is 1.0 mg/m³, in atmospheric air 0.3 mg/m³ (maximum one-time) and 0.1 mg/m³ (average daily). The damaging concentration of sulfuric acid vapor is 0.008 mg/l (exposure 60 min), lethal 0.18 mg/l (60 min). Hazard class II. An aerosol of sulfuric acid can form in the atmosphere as a result of emissions from chemical and metallurgical industries containing S oxides and fall in the form of acid rain.
Historical information
Sulfuric acid has been known since ancient times, occurring in nature in free form, for example, in the form of lakes near volcanoes. Perhaps the first mention of acid gases produced by the calcination of alum or iron sulfate of the “green stone” is found in writings attributed to the Arab alchemist Jabir ibn Hayyan.
In the 9th century, the Persian alchemist Ar-Razi, calcining a mixture of iron and copper sulfate (FeSO4 7H2O and CuSO4 5H2O), also obtained a solution of sulfuric acid. This method was improved by the European alchemist Albert Magnus, who lived in the 13th century.
Scheme for producing sulfuric acid from ferrous sulfate - thermal decomposition of iron (II) sulfate followed by cooling of the mixture
Dalton sulfuric acid molecule
- 2FeSO4+7H2O→Fe2O3+SO2+H2O+O2
- SO2+H2O+1/2O2 ⇆ H2SO4
The works of the alchemist Valentin (13th century) describe a method for producing sulfuric acid by absorbing gas (sulfuric anhydride) released by burning a mixture of sulfur and nitrate powders with water. Subsequently, this method formed the basis of the so-called. “chamber” method, carried out in small chambers lined with lead, which does not dissolve in sulfuric acid. In the USSR, this method existed until 1955.
Alchemists of the 15th century also knew a method for producing sulfuric acid from pyrite - sulfur pyrite, a cheaper and more common raw material than sulfur. Sulfuric acid has been produced in this way for 300 years, in small quantities in glass retorts. Subsequently, in connection with the development of catalysis, this method replaced the chamber method for the synthesis of sulfuric acid. Currently, sulfuric acid is produced by the catalytic oxidation (on V2O5) of sulfur (IV) oxide to sulfur (VI) oxide, and subsequent dissolution of sulfur (VI) oxide in 70% sulfuric acid to form oleum.
In Russia, the production of sulfuric acid was first organized in 1805 near Moscow in the Zvenigorod district. In 1913, Russia ranked 13th in the world in sulfuric acid production.
additional information
Tiny droplets of sulfuric acid can form in the middle and upper layers of the atmosphere as a result of the reaction of water vapor and volcanic ash containing large quantities of sulfur. The resulting suspension, due to the high albedo of sulfuric acid clouds, makes it difficult for sunlight to reach the surface of the planet. Therefore (and also as a result of the large number of tiny particles of volcanic ash in the upper atmosphere, which also impede sunlight access to the planet), significant climate changes can occur after particularly strong volcanic eruptions. For example, as a result of the eruption of the Ksudach volcano (Kamchatka Peninsula, 1907), an increased concentration of dust in the atmosphere remained for about 2 years, and characteristic noctilucent clouds of sulfuric acid were observed even in Paris. The explosion of Mount Pinatubo in 1991, which released 3 107 tons of sulfur into the atmosphere, resulted in 1992 and 1993 being significantly colder than 1991 and 1994.
Preparation of sulfuric acid
Main article: Sulfuric acid productionFirst way
Second way
In those rare cases when hydrogen sulfide (H2S) displaces sulfate (SO4-) from a salt (with metals Cu, Ag, Pb, Hg) the by-product is sulfuric acid
Sulfides of these metals have the highest strength, as well as a distinctive black color.
Standards
- Technical sulfuric acid GOST 2184-77
- Battery sulfuric acid. Technical specifications GOST 667-73
- Sulfuric acid of special purity. Technical specifications GOST 1422-78
- Reagents. Sulfuric acid. Technical specifications GOST 4204-77
Notes
- Ushakova N. N., Figurnovsky N. A. Vasily Mikhailovich Severgin: (1765-1826) / Ed. I. I. Shafranovsky. M.: Nauka, 1981. P. 59.
- 1 2 3 Khodakov Yu.V., Epshtein D.A., Gloriozov P.A. § 91. Chemical properties of sulfuric acid // Inorganic chemistry: Textbook for grades 7-8 of secondary school. - 18th ed. - M.: Education, 1987. - P. 209-211. - 240 s. - 1,630,000 copies.
- Khodakov Yu.V., Epshtein D.A., Gloriozov P.A. § 92. Qualitative reaction to sulfuric acid and its salts // Inorganic chemistry: Textbook for grades 7-8 of secondary school. - 18th ed. - M.: Education, 1987. - P. 212. - 240 p. - 1,630,000 copies.
- Bolshoi Theater artistic director Sergei Filin had sulfuric acid splashed on his face
- Epstein, 1979, p. 40
- Epstein, 1979, p. 41
- see article “Volcanoes and climate” (Russian)
- Russian archipelago - Is humanity to blame for global climate change? (Russian)
Literature
- Handbook of sulfuric acid, ed. K. M. Malina, 2nd ed., M., 1971
- Epstein D. A. General chemical technology. - M.: Chemistry, 1979. - 312 p.
Links
- Article “Sulfuric acid” (Chemical Encyclopedia)
- Density and pH value of sulfuric acid at t=20 °C
| Sulfates | |
|---|---|
|
Aluminum (KAl(SO4)2 12H2O) Ammonium aluminum sulfate ((NH4)Al(SO4)2) Ammonium iron sulfate (NH4Fe(SO4)2) Ammonium iron(II) sulfate (22) Ammonium iron(III) sulfate (NH4Fe(SO4)2) Ammonium cerium(IV) sulfate ((NH4)4Ce(SO4)4) Magnesium sulfate heptahydrate (MgSO4) Ammonium hydrogen sulfate ((NH4)HSO4) Potassium hydrogen sulfate (KHSO4) Sodium hydrogen sulfate (NaHSO4) Potassium disulfate (K2S2O7) Sodium disulfate (Na2S2O7) Iron(III) basic sulfate ((OH)2) Alum Vitriol Titanium oxide sulfate (TiOSO4) Oleum (H2SO4 xSO3) Pyrosulfuric acid (H2S2O7) (H2SO4) Tutton's salts Actinium(III) sulfate ( Ac2(SO4)3) Aluminum sulfate (Al2(SO4)3) Aluminum sulfate (NaAl(SO4)2) Ammonium sulfate ((NH4)2SO4) Barium sulfate (BaSO4) Beryllium sulfate (BeSO4) Vanadyl sulfate (VOSO4) Vanadium sulfate( III) (V2(SO4)3) Bismuth sulfate (Bi2(SO4)3) Hydroxyammonium sulfate ((NH3OH)2SO4) Iron(II) sulfate (FeSO4) Iron(III) sulfate (Fe2(SO4)3) Indium(III) sulfate ) (In2(SO4)3) Iridium(III) sulfate (Ir2(SO4)3) Cadmium sulfate (CdSO4) Potassium sulfate (K2SO4) Calcium sulfate (CaSO4) Cobalt(II) sulfate (CoSO4) Cobalt(III) sulfate (Co2 (SO4)3) Lithium sulfate (Li2SO4) Magnesium sulfate (MgSO4) Manganese(II) sulfate (MnSO4) Manganese(III) sulfate (Mn2(SO4)3) Copper(I) sulfate (Cu2SO4) Copper(II) sulfate (CuSO4 ) Sodium sulfate (Na2SO4) Nickel(II) sulfate (NiSO4) Tin(II) sulfate (SnSO4) Praseodymium sulfate (Pr2(SO4)3) Mercury(I) sulfate (Hg2SO4) Mercury(II) sulfate (HgSO4) Lead sulfate( II) (PbSO4) Silver sulfate (Ag2SO4) Strontium sulfate (SrSO4) Antimony sulfate (Sb2(SO4)3) Thallium(I) sulfate (Tl2SO4) Thallium(III) sulfate (Tl2(SO4)3) Tetraammine copper(II) sulfate ( Cu(NH3)4SO4) Titanium(III) sulfate (Ti2(SO4)3) Titanium(IV) sulfate (Ti(SO4)2) Uranium sulfate (U(SO4)2) Uranyl sulfate (UO2SO4) Chromium(III) sulfate ( Cr2(SO4)3) Chromium(III)-potassium sulfate (KCr(SO4)2) Cesium sulfate (Cs2SO4) Cerium(IV) sulfate (Ce(SO4)2) Zinc sulfate (ZnSO4) Zirconium sulfate (Zr(SO4)2 ) |
sulfuric acid, sulfuric acid Wikipedia, sulfuric acid hydrolysis, sulfuric acid its effect 1, sulfuric acid hazard class, buy sulfuric acid in Ukraine, sulfuric acid application, sulfuric acid corrodes, sulfuric acid with water, sulfuric acid formula
