physical properties.

Pure 100% sulfuric acid (monohydrate) is a colorless oily liquid that solidifies into a crystalline mass at +10 °C. Reactive sulfuric acid usually has a density of 1.84 g/cm 3 and contains about 95% H 2 SO 4 . It hardens only below -20 °C.

The melting point of the monohydrate is 10.37 °C with a heat of fusion of 10.5 kJ/mol. V normal conditions it is a very viscous liquid with a very high dielectric constant (e = 100 at 25°C). Insignificant own electrolytic dissociation of the monohydrate proceeds in parallel in two directions: [Н 3 SO 4 + ]·[НSO 4 - ] = 2 10 -4 and [Н 3 О + ]·[НS 2 О 7 - ] = 4 10 - 5 . Its molecular-ionic composition can be approximately characterized by the following data (in %):

H2SO4 HSO 4- H3SO4+ H3O+ HS 2 O 7 - H2S2O7 99,5 0,18 0,14 0,09 0,05 0,04

When even small amounts of water are added, dissociation becomes predominant according to the scheme:

H 2 O + H 2 SO 4<==>H 3 O + + HSO 4 -

Chemical properties.

H 2 SO 4 is a strong dibasic acid.

H2SO4<-->H + + HSO 4 -<-->2H + + SO 4 2-

The first stage (for medium concentrations) leads to 100% dissociation:

K 2 \u003d ( ) / \u003d 1.2 10 -2

1) Interaction with metals:

a) dilute sulfuric acid dissolves only metals that are in the series of voltages to the left of hydrogen:

Zn 0 + H 2 +1 SO 4 (razb) --> Zn +2 SO 4 + H 2 O

b) concentrated H 2 +6 SO 4 - a strong oxidizing agent; when interacting with metals (except Au, Pt) it can be reduced to S +4 O 2, S 0 or H 2 S -2 (Fe, Al, Cr also do not react without heating - they are passivated):

2Ag 0 + 2H 2 +6 SO 4 --> Ag 2 +1 SO 4 + S +4 O 2 + 2H 2 O

8Na 0 + 5H 2 +6 SO 4 --> 4Na 2 +1 SO 4 + H 2 S -2 + 4H 2 O

2) concentrated H 2 S +6 O 4 reacts when heated with some non-metals due to its strong oxidizing properties, turning into sulfur compounds of a lower oxidation state, (for example, S + 4 O 2):

С 0 + 2H 2 S +6 O 4 (conc) --> C +4 O 2 + 2S +4 O 2 + 2H 2 O

S 0 + 2H 2 S +6 O 4 (conc) --> 3S +4 O 2 + 2H 2 O

2P 0 + 5H 2 S +6 O 4 (conc) --> 5S +4 O 2 + 2H 3 P +5 O 4 + 2H 2 O

3) with basic oxides:

CuO + H2SO4 --> CuSO4 + H2O

CuO + 2H + --> Cu 2+ + H 2 O

4) with hydroxides:

H 2 SO 4 + 2NaOH --> Na 2 SO 4 + 2H 2 O

H + + OH - --> H 2 O

H 2 SO 4 + Cu(OH) 2 --> CuSO 4 + 2H 2 O

2H + + Cu(OH) 2 --> Cu 2+ + 2H 2 O

5) exchange reactions with salts:

BaCl 2 + H 2 SO 4 --> BaSO 4 + 2HCl

Ba 2+ + SO 4 2- --> BaSO 4

The formation of a white precipitate of BaSO 4 (insoluble in acids) is used to identify sulfuric acid and soluble sulfates.

The monohydrate (pure, 100% sulfuric acid) is an ionizing solvent having an acidic character. Sulfates of many metals are well dissolved in it (turning into bisulfates), while salts of other acids are dissolved, as a rule, only if their solvolysis is possible (with conversion to bisulfates). Nitric acid behaves in monohydrate as weak base

HNO 3 + 2 H 2 SO 4<==>H 3 O + + NO 2 + + 2 HSO 4 -

perchloric - as a very weak acid

H 2 SO 4 + HClO 4 = H 3 SO 4 + + ClO 4 -

Fluorosulfonic and chlorosulfonic acids are somewhat stronger (HSO 3 F> HSO 3 Cl> HClO 4). The monohydrate dissolves well many organic substances containing atoms with unshared electron pairs (capable of attaching a proton). Some of these can then be isolated back unchanged by simply diluting the solution with water. The monohydrate has a high cryoscopic constant (6.12°) and is sometimes used as a medium for determining molecular weights.

Concentrated H 2 SO 4 is a fairly strong oxidizing agent, especially when heated (it is usually reduced to SO 2). For example, it oxidizes HI and partially HBr (but not HCl) to free halogens. It also oxidizes many metals - Cu, Hg, etc. (whereas gold and platinum are stable with respect to H 2 SO 4). So the interaction with copper goes according to the equation:

Cu + 2 H 2 SO 4 \u003d CuSO 4 + SO 2 + H 2 O

Acting as an oxidizing agent, sulfuric acid is usually reduced to SO 2 . However, it can be reduced to S and even H 2 S with the strongest reducing agents. Concentrated sulfuric acid reacts with hydrogen sulfide according to the equation:

H 2 SO 4 + H 2 S \u003d 2H 2 O + SO 2 + S

It should be noted that it is also partially reduced by gaseous hydrogen and therefore cannot be used to dry it.

Rice. 13. Electrical conductivity of sulfuric acid solutions.

The dissolution of concentrated sulfuric acid in water is accompanied by a significant release of heat (and some decrease in the total volume of the system). Monohydrate almost does not conduct electricity. In contrast, aqueous solutions of sulfuric acid are good conductors. As seen in fig. 13, approximately 30% acid has the maximum electrical conductivity. The minimum of the curve corresponds to a hydrate with the composition H 2 SO 4 ·H 2 O.

The release of heat upon dissolution of the monohydrate in water is (depending on the final concentration of the solution) up to 84 kJ/mol H 2 SO 4 . On the contrary, by mixing 66% sulfuric acid, pre-cooled to 0 °C, with snow (1:1 by weight), a temperature drop can be achieved, down to -37 °C.

The change in the density of aqueous solutions of H 2 SO 4 with its concentration (wt.%) is given below:

5 10 20 30 40 50 60 15 °С 1,033 1,068 1,142 1,222 1,307 1,399 1,502 25 °С 1,030 1,064 1,137 1,215 1,299 1,391 1,494

70 80 90 95 97 100 15 °С 1,615 1,732 1,820 1,839 1,841 1,836 25 °С 1,606 1,722 1,809 1,829 1,831 1,827

As can be seen from these data, the determination of the density of the concentration of sulfuric acid above 90 wt. % becomes quite inaccurate.

Water vapor pressure over H 2 SO 4 solutions of different concentrations at different temperatures is shown in fig. 15. Sulfuric acid can act as a drying agent only as long as the water vapor pressure above its solution is less than its partial pressure in the gas being dried.

Rice. 15. Water vapor pressure.

Rice. 16. Boiling points over solutions of H 2 SO 4 . H 2 SO 4 solutions.

When a dilute sulfuric acid solution is boiled, water is distilled off from it, and the boiling point rises up to 337 ° C, when 98.3% H 2 SO 4 begins to distill (Fig. 16). On the contrary, excess sulfuric anhydride volatilizes from more concentrated solutions. The steam of sulfuric acid boiling at 337 ° C is partially dissociated into H 2 O and SO 3, which recombine upon cooling. The high boiling point of sulfuric acid allows it to be used to isolate volatile acids from their salts (for example, HCl from NaCl) when heated.

Receipt.

The monohydrate can be obtained by crystallization of concentrated sulfuric acid at -10°C.

Sulfuric acid production.

1st stage. Pyrite kiln.

4FeS 2 + 11O 2 --> 2Fe 2 O 3 + 8SO 2 + Q

The process is heterogeneous:

1) grinding iron pyrite (pyrite)

2) "fluidized bed" method

3) 800°С; removal of excess heat

4) increase in the concentration of oxygen in the air

2nd stage.After cleaning, drying and heat exchange, sulfur dioxide enters the contact apparatus, where it is oxidized to sulfuric anhydride (450 ° C - 500 ° C; catalyst V 2 O 5):

2SO2 + O2<-->2SO3

3rd stage. Absorption tower:

nSO 3 + H 2 SO 4 (conc) --> (H 2 SO 4 nSO 3) (oleum)

Water cannot be used due to the formation of fog. Apply ceramic nozzles and the principle of counterflow.

Application.

Remember! Sulfuric acid must be poured into water in small portions, and not vice versa. Otherwise, a violent chemical reaction may occur, as a result of which a person may receive severe burns.

Sulphuric acid- one of the main products of the chemical industry. It goes to the production of mineral fertilizers (superphosphate, ammonium sulfate), various acids and salts, medicines and detergents, dyes, artificial fibers, explosives. It is used in metallurgy (decomposition of ores, for example, uranium), for the purification of petroleum products, as a desiccant, etc.

Practically important is the fact that very strong (above 75%) sulfuric acid does not act on iron. This allows you to store and transport it in steel tanks. On the contrary, dilute H 2 SO 4 easily dissolves iron with the release of hydrogen. Oxidizing properties are not typical for it at all.

Strong sulfuric acid absorbs moisture vigorously and is therefore often used to dry gases. From many organic substances containing hydrogen and oxygen, it takes away water, which is often used in technology. With the same (as well as with the oxidizing properties of strong H 2 SO 4) its destructive effect on plant and animal tissues is associated. Sulfuric acid that accidentally gets on the skin or dress during work should be immediately washed off with plenty of water, then moisten the affected area with a dilute ammonia solution and rinse again with water.

Molecules of pure sulfuric acid.

Fig.1. Diagram of hydrogen bonds in an H 2 SO 4 crystal.

The molecules that form the monohydrate crystal, (HO) 2 SO 2 are connected to each other by fairly strong (25 kJ/mol) hydrogen bonds, as shown schematically in Fig. 1. The (HO) 2 SO 2 molecule itself has the structure of a distorted tetrahedron with a sulfur atom near the center and is characterized by the following parameters: (d (S-OH) = 154 pm, PHO-S-OH = 104 °, d (S = O) \u003d 143 pm, ROSO \u003d 119 ° In the HOSO 3 - ion, d (S-OH) \u003d 161 and d (SO) \u003d 145 pm, and when going to the SO 4 ion, the 2-tetrahedron acquires the correct shape and the parameters are aligned.

Sulfuric acid hydrates.

For sulfuric acid, several crystalline hydrates are known, the composition of which is shown in Fig. 14. Of these, the poorest in water is the oxonium salt: H 3 O + HSO 4 -. Since the system under consideration is very prone to supercooling, the freezing temperatures actually observed in it are much lower than the melting points.

Rice. 14. Melting points in the H 2 O·H 2 SO 4 system.

Sulfur is chemical element, which is in the sixth group and third period of the periodic table. In this article, we will take a detailed look at its chemical and production, use, and so on. The physical characteristic includes such features as color, electrical conductivity level, sulfur boiling point, etc. The chemical one describes its interaction with other substances.

Sulfur in terms of physics

This is a fragile substance. Under normal conditions, it is in a solid state of aggregation. Sulfur has a lemon yellow color.

And for the most part, all its compounds have yellow tints. Does not dissolve in water. It has low thermal and electrical conductivity. These features characterize it as a typical non-metal. Though chemical composition sulfur is not at all complicated, this substance can have several variations. It all depends on the structure. crystal lattice, with the help of which atoms are connected, but they do not form molecules.

So, the first option is rhombic sulfur. She is the most stable. The boiling point of this type of sulfur is four hundred and forty-five degrees Celsius. But in order for a given substance to pass into a gaseous state of aggregation, it must first pass through a liquid state. So, the melting of sulfur occurs at a temperature that is one hundred and thirteen degrees Celsius.

The second option is monoclinic sulfur. It is a needle-shaped crystals with a dark yellow color. The melting of sulfur of the first type, and then its slow cooling leads to the formation of this type. This variety has almost the same physical characteristics. For example, the boiling point of sulfur of this type is still the same four hundred and forty-five degrees. In addition, there is such a variety of this substance as plastic. It is obtained by pouring into cold water heated almost to a boil rhombic. The boiling point of sulfur of this type is the same. But the substance has the property of stretching like rubber.

Another component physical characteristics, which I would like to talk about, is the ignition temperature of sulfur.

This indicator may vary depending on the type of material and its origin. For example, the ignition temperature of technical sulfur is one hundred and ninety degrees. This is a rather low figure. In other cases, the flash point of sulfur can be two hundred and forty-eight degrees and even two hundred and fifty-six. It all depends on what material it was mined from, what density it has. But we can conclude that the combustion temperature of sulfur is quite low, compared with other chemical elements, it is a flammable substance. In addition, sometimes sulfur can combine into molecules consisting of eight, six, four or two atoms. Now, having considered sulfur from the point of view of physics, let's move on to the next section.

Chemical characterization of sulfur

This element has a relatively low atomic mass, it is equal to thirty-two grams per mole. The characteristic of the sulfur element includes such a feature of this substance as the ability to have different degrees of oxidation. In this it differs from, say, hydrogen or oxygen. Considering the question of what chemical characterization element sulfur, it is impossible not to mention that, depending on the conditions, it exhibits both reducing and oxidizing properties. So, in order, consider the interaction of a given substance with various chemical compounds.

Sulfur and simple substances

Simple substances are substances that contain only one chemical element. Its atoms may combine into molecules, as, for example, in the case of oxygen, or they may not combine, as is the case with metals. So, sulfur can react with metals, other non-metals and halogens.

Interaction with metals

A high temperature is required to carry out this kind of process. Under these conditions, an addition reaction occurs. That is, metal atoms combine with sulfur atoms, thus forming complex substances sulfides. For example, if you heat two moles of potassium by mixing them with one mole of sulfur, you get one mole of the sulfide of this metal. The equation can be written in the following form: 2K + S = K 2 S.

Reaction with oxygen

This is sulfur burning. As a result of this process, its oxide is formed. The latter can be of two types. Therefore, the combustion of sulfur can occur in two stages. The first is when one mole of sulfur and one mole of oxygen form one mole of sulfur dioxide. Write down the equation for this chemical reaction can be as follows: S + O 2 \u003d SO 2. The second stage is the addition of one more oxygen atom to the dioxide. This happens if you add one mole of oxygen to two moles at high temperature. The result is two moles of sulfur trioxide. The equation for this chemical interaction looks like this: 2SO 2 + O 2 = 2SO 3. As a result of this reaction, sulfuric acid is formed. So, by carrying out the two processes described, it is possible to pass the resulting trioxide through a jet of water vapor. And we get The equation for such a reaction is written as follows: SO 3 + H 2 O \u003d H 2 SO 4.

Interaction with halogens

Chemical like other non-metals, allow it to react with this group of substances. It includes compounds such as fluorine, bromine, chlorine, iodine. Sulfur reacts with any of them, except for the last one. As an example, we can cite the process of fluorination of the element of the periodic table we are considering. By heating the mentioned non-metal with a halogen, two variations of fluoride can be obtained. The first case: if we take one mole of sulfur and three moles of fluorine, we get one mole of fluoride, the formula of which is SF 6. The equation looks like this: S + 3F 2 = SF 6. In addition, there is a second option: if we take one mole of sulfur and two moles of fluorine, we get one mole of fluoride with the chemical formula SF 4 . The equation is written in the following form: S + 2F 2 = SF 4 . As you can see, it all depends on the proportions in which the components are mixed. In exactly the same way, it is possible to carry out the process of chlorination of sulfur (two different substances can also be formed) or bromination.

Interaction with other simple substances

The characterization of the element sulfur does not end there. The substance can also enter into a chemical reaction with hydrogen, phosphorus and carbon. Due to the interaction with hydrogen, sulfide acid is formed. As a result of its reaction with metals, their sulfides can be obtained, which, in turn, are also obtained by direct reaction of sulfur with the same metal. The addition of hydrogen atoms to sulfur atoms occurs only under conditions of very high temperature. When sulfur reacts with phosphorus, its phosphide is formed. It has the following formula: P 2 S 3. In order to get one mole of this substance, you need to take two moles of phosphorus and three moles of sulfur. When sulfur interacts with carbon, the carbide of the considered non-metal is formed. Its chemical formula looks like this: CS 2. In order to get one mole of this substance, you need to take one mole of carbon and two moles of sulfur. All the addition reactions described above occur only when the reactants are heated to high temperatures. We have considered the interaction of sulfur with simple substances, now let's move on to the next point.

Sulfur and complex compounds

Compounds are those substances whose molecules consist of two (or more) different elements. Chemical properties sulfur allows it to react with compounds such as alkalis, as well as concentrated sulfate acid. Its reactions with these substances are rather peculiar. First, consider what happens when the non-metal in question is mixed with alkali. For example, if we take six moles and add three moles of sulfur to them, we get two moles of potassium sulfide, one mole of this metal sulfite and three moles of water. This kind of reaction can be expressed by the following equation: 6KOH + 3S \u003d 2K 2 S + K2SO 3 + 3H 2 O. By the same principle, the interaction occurs if you add Next, consider the behavior of sulfur when a concentrated solution of sulfate acid is added to it. If we take one mole of the first and two moles of the second substance, we get the following products: sulfur trioxide in the amount of three moles, and also water - two moles. This chemical reaction can only take place when the reactants are heated to a high temperature.

Obtaining the considered non-metal

There are several main methods by which sulfur can be extracted from a variety of substances. The first method is to isolate it from pyrite. Chemical formula the last - FeS 2 . When this substance is heated to a high temperature without access to oxygen, another iron sulfide - FeS - and sulfur can be obtained. The reaction equation is written as follows: FeS 2 \u003d FeS + S. The second method of obtaining sulfur, which is often used in industry, is the combustion of sulfur sulfide under the condition of a small amount of oxygen. In this case, you can get the considered non-metal and water. To carry out the reaction, you need to take the components in a molar ratio of two to one. As a result, we get the final products in proportions of two to two. The equation for this chemical reaction can be written as follows: 2H 2 S + O 2 \u003d 2S + 2H 2 O. In addition, sulfur can be obtained during various metallurgical processes, for example, in the production of metals such as nickel, copper and others.

Industrial use

The non-metal we are considering has found its widest application in the chemical industry. As mentioned above, here it is used to obtain sulfate acid from it. In addition, sulfur is used as a component for the manufacture of matches, due to the fact that it is a flammable material. It is also indispensable in the production of explosives, gunpowder, sparklers, etc. In addition, sulfur is used as one of the ingredients in pest control products. In medicine, it is used as a component in the manufacture of drugs for skin diseases. Also, the substance in question is used in the production of various dyes. In addition, it is used in the manufacture of phosphors.

Electronic structure of sulfur

As you know, all atoms consist of a nucleus, in which there are protons - positively charged particles - and neutrons, i.e. particles that have a zero charge. Electrons revolve around the nucleus with a negative charge. For an atom to be neutral, it must have the same number of protons and electrons in its structure. If there are more of the latter, this is already a negative ion - an anion. If, on the contrary, the number of protons is greater than the number of electrons, this is a positive ion, or cation. The sulfur anion can act as an acid residue. It is part of the molecules of substances such as sulfide acid (hydrogen sulfide) and metal sulfides. An anion is formed during electrolytic dissociation that occurs when a substance dissolves in water. In this case, the molecule decomposes into a cation, which can be represented as a metal or hydrogen ion, as well as a cation - an ion of an acid residue or a hydroxyl group (OH-).

Since the serial number of sulfur in the periodic table is sixteen, we can conclude that exactly this number of protons is located in its nucleus. Based on this, we can say that there are also sixteen electrons rotating around. The number of neutrons can be found by subtracting from molar mass the serial number of a chemical element: 32 - 16 = 16. Each electron does not rotate randomly, but in a certain orbit. Since sulfur is a chemical element that belongs to the third period of the periodic table, there are three orbits around the nucleus. The first one has two electrons, the second has eight, and the third has six. Electronic formula the sulfur atom is written as follows: 1s2 2s2 2p6 3s2 3p4.

Prevalence in nature

Basically, the considered chemical element is found in the composition of minerals, which are sulfides of various metals. First of all, it is pyrite - iron salt; it is also lead, silver, copper luster, zinc blende, cinnabar - mercury sulfide. In addition, sulfur can also be included in the composition of minerals, the structure of which is represented by three or more chemical elements.

For example, chalcopyrite, mirabilite, kieserite, gypsum. You can consider each of them in more detail. Pyrite is a ferrum sulfide, or FeS 2 . It has a light yellow color with a golden sheen. This mineral can often be found as an impurity in lapis lazuli, which is widely used to make jewelry. This is due to the fact that these two minerals often have a common deposit. Copper shine - chalcocite, or chalcosine - is a bluish-gray substance, similar to metal. and silver luster (argentite) have similar properties: they both look like metals, have a gray color. Cinnabar is a brownish-red dull mineral with gray patches. Chalcopyrite, whose chemical formula is CuFeS 2 , is golden yellow, it is also called golden blende. Zinc blende (sphalerite) can have a color from amber to fiery orange. Mirabilite - Na 2 SO 4 x10H 2 O - transparent or white crystals. It is also called used in medicine. The chemical formula of kieserite is MgSO 4 xH 2 O. It looks like a white or colorless powder. The chemical formula of gypsum is CaSO 4 x2H 2 O. In addition, this chemical element is part of the cells of living organisms and is an important trace element.

properties of sulfuric acid

Anhydrous sulfuric acid (monohydrate) is a heavy oily liquid that mixes with water in all proportions with the release of a large amount of heat. The density at 0 ° C is 1.85 g / cm 3. It boils at 296°C and freezes at -10°C. Sulfuric acid is called not only monohydrate, but also its aqueous solutions (), as well as solutions of sulfur trioxide in monohydrate (), called oleum. Oleum "smokes" in air due to desorption from it. Pure sulfuric acid is colorless, while commercial acid is dark in color with impurities.

Physical Properties sulfuric acid, such as density, crystallization temperature, boiling point, depend on its composition. On fig. 1 shows a crystallization diagram of the system. The maxima in it correspond to the composition of the compounds or, the presence of minima is explained by the fact that the crystallization temperature of mixtures of two substances is lower than the crystallization temperature of each of them.

Rice. one

Anhydrous 100% sulfuric acid has a relatively high crystallization temperature of 10.7 °C. To reduce the possibility of freezing of a commercial product during transportation and storage, the concentration of technical sulfuric acid is chosen such that it has a sufficiently low crystallization temperature. The industry produces three types of commercial sulfuric acid.

Sulfuric acid is very active. It dissolves metal oxides and most pure metals; at elevated temperatures it displaces all other acids from salts. Especially greedily sulfuric acid combines with water due to its ability to give hydrates. It takes away water from other acids, from crystalline salts and even oxygen derivatives of hydrocarbons, which contain not water itself, but hydrogen and oxygen in combination H: O = 2. wood and other plant and animal tissues containing cellulose, starch and sugar are destroyed in concentrated sulfuric acid; water binds with acid and only finely dispersed carbon remains from the tissue. In dilute acid, cellulose and starch break down to form sugars. If it comes into contact with human skin, concentrated sulfuric acid causes burns.

The high activity of sulfuric acid, combined with the relatively low cost of production, predetermined the enormous scale and extreme variety of its application (Fig. 2). It is difficult to find an industry that has not consumed sulfuric acid or products made from it in various quantities.

Rice. 2

The largest consumer of sulfuric acid is the production of mineral fertilizers: superphosphate, ammonium sulfate, and others. Many acids (for example, phosphoric, acetic, hydrochloric) and salts are produced largely with the help of sulfuric acid. Sulfuric acid is widely used in the production of non-ferrous and rare metals. In the metalworking industry, sulfuric acid or its salts are used to pickle steel products before painting, tinning, nickel plating, chromium plating, etc. Significant amounts of sulfuric acid are used to refine petroleum products. Obtaining a number of dyes (for fabrics), varnishes and paints (for buildings and machines), medicinal substances and some plastics is also associated with the use of sulfuric acid. With the help of sulfuric acid, ethyl and other alcohols, some esters, synthetic detergents, a number of pesticides for combating agricultural pests and weeds are produced. Dilute solutions of sulfuric acid and its salts are used in the production of rayon, in the textile industry for processing fibers or fabrics before dyeing them, as well as in other industries. light industry. In the food industry, sulfuric acid is used in the production of starch, molasses and a number of other products. Transport uses lead sulfuric acid batteries. Sulfuric acid is used for drying gases and for concentrating acids. Finally, sulfuric acid is used in nitration processes and in the manufacture of most explosives.

Sulfuric acid (H2SO4) is one of the most caustic acids and dangerous reagents, known to man especially in concentrated form. Chemically pure sulfuric acid is a heavy toxic liquid of oily consistency, odorless and colorless. It is obtained by the oxidation of sulfur dioxide (SO2) by the contact method.

At a temperature of + 10.5 ° C, sulfuric acid turns into a frozen glassy crystalline mass, greedily, like a sponge, absorbing moisture from environment. In industry and chemistry, sulfuric acid is one of the main chemical compounds and occupies a leading position in terms of production in tons. That is why sulfuric acid is called the "blood of chemistry". Sulfuric acid is used to make fertilizers medications, other acids, large , fertilizers and much more.

Basic physical and chemical properties of sulfuric acid

1. Sulfuric acid in its pure form (formula H2SO4), at a concentration of 100%, is a colorless thick liquid. Most important property H2SO4 is highly hygroscopic - the ability to take water out of the air. This process is accompanied by a massive release of heat.
2. H2SO4 is a strong acid.
3. Sulfuric acid is called monohydrate - it contains 1 mol of H2O (water) per 1 mol of SO3. Because of its impressive hygroscopic properties, it is used to extract moisture from gases.
4. Boiling point - 330 ° C. In this case, the acid is decomposed into SO3 and water. Density - 1.84. Melting point - 10.3 ° C /.
5. Concentrated sulfuric acid is a powerful oxidizing agent. To start the redox reaction, the acid must be heated. The result of the reaction is SO2. S+2H2SO4=3SO2+2H2O
6. Depending on the concentration, sulfuric acid reacts differently with metals. In a dilute state, sulfuric acid is capable of oxidizing all metals that are in the series of voltages to hydrogen. An exception is made as the most resistant to oxidation. Dilute sulfuric acid reacts with salts, bases, amphoteric and basic oxides. Concentrated sulfuric acid is capable of oxidizing all metals in the series of voltages, and silver too.
7. Sulfuric acid forms two types of salts: acidic (hydrosulfates) and medium (sulfates)
8. H2SO4 actively reacts with organic matter and non-metals, some of which it can turn into coal.
9. Sulfuric anhydrite is perfectly soluble in H2SO4, and in this case oleum is formed - a solution of SO3 in sulfuric acid. Outwardly, it looks like this: fuming sulfuric acid, releasing sulfuric anhydrite.
10. Sulfuric acid in aqueous solutions is a strong dibasic acid, and when it is added to water, a huge amount of heat is released. When preparing dilute solutions of H2SO4 from concentrated ones, it is necessary to add a heavier acid to water in a small stream, and not vice versa. This is done to avoid boiling water and splashing acid.

Concentrated and dilute sulfuric acids

Concentrated solutions of sulfuric acid include solutions from 40%, capable of dissolving silver or palladium.

Dilute sulfuric acid includes solutions whose concentration is less than 40%. These are not such active solutions, but they are able to react with brass and copper.

Getting sulfuric acid

The production of sulfuric acid on an industrial scale was launched in the 15th century, but at that time it was called "vitriol". If earlier humanity consumed only a few tens of liters of sulfuric acid, then in modern world the calculation goes to millions of tons per year.

The production of sulfuric acid is carried out industrially, and there are three of them:

1. contact method.
2. nitrous method
3. Other Methods

Let's talk in detail about each of them.

contact production method

The contact method of production is the most common, and it performs the following tasks:

• It turns out a product that satisfies the needs of the maximum number of consumers.
• During production, harm to the environment is reduced.

In the contact method, the following substances are used as raw materials:

• pyrite (sulfur pyrites);
• sulfur;
• vanadium oxide (this substance causes the role of a catalyst);
• hydrogen sulfide;
• sulfides of various metals.

Before starting the production process, raw materials are pre-prepared. To begin with, in special crushing plants, pyrite is subjected to grinding, which allows, due to an increase in the contact area active substances, speed up the reaction. Pyrite undergoes purification: it is lowered into large containers of water, during which waste rock and all kinds of impurities float to the surface. They are removed at the end of the process.

The production part is divided into several stages:

1. After crushing, pyrite is cleaned and sent to the furnace - where it is fired at temperatures up to 800 ° C. According to the principle of counterflow, air is supplied to the chamber from below, and this ensures that the pyrite is in a suspended state. Today, this process takes a few seconds, but earlier it took several hours to fire. During the roasting process, wastes appear in the form of iron oxide, which are removed and subsequently transferred to the enterprises of the metallurgical industry. During firing, water vapor, O2 and SO2 gases are released. When the purification from water vapor and the smallest impurities is completed, pure sulfur oxide and oxygen are obtained.
2. In the second stage, an exothermic reaction takes place under pressure using a vanadium catalyst. The start of the reaction starts when the temperature reaches 420 °C, but it can be increased to 550 °C in order to increase efficiency. During the reaction, catalytic oxidation occurs and SO2 becomes SO3.
3. The essence of the third stage of production is as follows: the absorption of SO3 in the absorption tower, during which the oleum H2SO4 is formed. In this form, H2SO4 is poured into special containers (it does not react with steel) and is ready to meet the end user.

During production, as we said above, a lot of thermal energy is generated, which is used for heating purposes. Many sulfuric acid plants install steam turbines that use the exhaust steam to generate additional electricity.

Nitrous process for the production of sulfuric acid

Despite the advantages of the contact method of production, which produces more concentrated and pure sulfuric acid and oleum, quite a lot of H2SO4 is produced by the nitrous method. In particular, at superphosphate plants.

For the production of H2SO4, sulfur dioxide acts as the initial substance, both in the contact and in the nitrous method. It is obtained specifically for these purposes by burning sulfur or roasting sulfurous metals.

The conversion of sulfur dioxide into sulfurous acid consists in the oxidation of sulfur dioxide and the addition of water. The formula looks like this:
SO2 + 1|2 O2 + H2O = H2SO4

But sulfur dioxide does not directly react with oxygen, therefore, with the nitrous method, the oxidation of sulfur dioxide is carried out using nitrogen oxides. Higher oxides of nitrogen (we are talking about nitrogen dioxide NO2, nitrogen trioxide NO3) in this process are reduced to nitric oxide NO, which is subsequently again oxidized by oxygen to higher oxides.

The production of sulfuric acid by the nitrous method is technically formalized in two ways:

• Chamber.
• Tower.

The nitrous method has a number of advantages and disadvantages.

Disadvantages of the nitrous method:

• It turns out 75% sulfuric acid.
• Product quality is low.
• Incomplete return of nitrogen oxides (addition of HNO3). Their emissions are harmful.
• The acid contains iron, nitrogen oxides and other impurities.

Advantages of the nitrous method:

• The cost of the process is lower.
• The possibility of processing SO2 at 100%.
• Simplicity of hardware design.

Major Russian Sulfuric Acid Plants

The annual production of H2SO4 in our country is calculated in six figures - about 10 million tons. The leading producers of sulfuric acid in Russia are companies that are, in addition, its main consumers. It's about about companies whose field of activity is the production of mineral fertilizers. For example, "Balakovo mineral fertilizers", "Ammophos".

Crimean Titan, the largest producer of titanium dioxide in Eastern Europe, operates in Armyansk, Crimea. In addition, the plant is engaged in the production of sulfuric acid, mineral fertilizers, iron sulphate, etc.

Sulfuric acid of various types is produced by many plants. For example, battery sulfuric acid is produced by: Karabashmed, FKP Biysk Oleum Plant, Svyatogor, Slavia, Severkhimprom, etc.

Oleum is produced by UCC Shchekinoazot, FKP Biysk Oleum Plant, Ural Mining and Metallurgical Company, Kirishinefteorgsintez Production Association, etc.

Sulfuric acid of high purity is produced by UCC Shchekinoazot, Component-Reaktiv.

Spent sulfuric acid can be bought at the plants ZSS, HaloPolymer Kirovo-Chepetsk.

Manufacturers of technical sulfuric acid are Promsintez, Khiprom, Svyatogor, Apatit, Karabashmed, Slavia, Lukoil-Permnefteorgsintez, Chelyabinsk Zinc Plant, Electrozinc, etc.

Due to the fact that pyrite is the main raw material in the production of H2SO4, and this is a waste product of enrichment enterprises, its suppliers are the Norilsk and Talnakh enrichment plants.

The leading world positions in the production of H2SO4 are occupied by the USA and China, which account for 30 million tons and 60 million tons, respectively.

Scope of sulfuric acid

The world annually consumes about 200 million tons of H2SO4, from which a wide range of products is produced. Sulfuric acid rightfully holds the palm among other acids in terms of industrial use.

As you already know, sulfuric acid is one of the most important products of the chemical industry, so the scope of sulfuric acid is quite wide. The main uses of H2SO4 are as follows:

• Sulfuric acid is used in huge volumes for the production of mineral fertilizers, and it takes about 40% of the total tonnage. For this reason, plants producing H2SO4 are being built next to fertilizer plants. These are ammonium sulfate, superphosphate, etc. In their production, sulfuric acid is taken in its pure form (100% concentration). It will take 600 liters of H2SO4 to produce a ton of ammophos or superphosphate. It is these fertilizers that are most often used in agriculture.
• H2SO4 is used to make explosives.
• Purification of petroleum products. To obtain kerosene, gasoline, mineral oils, hydrocarbon purification is required, which occurs with the use of sulfuric acid. In the process of refining oil for the purification of hydrocarbons, this industry "takes" as much as 30% of the world's tonnage of H2SO4. In addition, the octane number of fuel is increased with sulfuric acid and wells are treated during oil production.
• in the metallurgical industry. Sulfuric acid is used in metallurgy to remove scale and rust from wire, sheet metal, as well as to reduce aluminum in the production of non-ferrous metals. Before coating metal surfaces with copper, chromium or nickel, the surface is etched with sulfuric acid.
• In the manufacture of medicines.
• in the production of paints.
• in the chemical industry. H2SO4 is used in the production of detergents, ethyl detergent, insecticides, etc., and these processes are impossible without it.
• To obtain other known acids, organic and inorganic compounds used for industrial purposes.

Sulfuric acid salts and their uses

Most important salts sulfuric acid:

• Glauber's salt Na2SO4 10H2O (crystalline sodium sulfate). The scope of its application is quite capacious: the production of glass, soda, in veterinary medicine and medicine.
• Barium sulfate BaSO4 is used in the production of rubber, paper, white mineral paint. In addition, it is indispensable in medicine for fluoroscopy of the stomach. It is used to make "barium porridge" for this procedure.
• Calcium sulfate CaSO4. In nature, it can be found in the form of gypsum CaSO4 2H2O and anhydrite CaSO4. Gypsum CaSO4 2H2O and calcium sulfate are used in medicine and construction. With gypsum, when heated to a temperature of 150 - 170 ° C, partial dehydration occurs, as a result of which burnt gypsum, known to us as alabaster, is obtained. Kneading alabaster with water to the consistency of batter, the mass quickly hardens and turns into a kind of stone. It is this property of alabaster that is actively used in construction work: casts and molds are made from it. In plastering work, alabaster is indispensable as a binder. Patients of trauma departments are given special fixing solid bandages - they are made on the basis of alabaster.
• Ferrous vitriol FeSO4 7H2O is used for the preparation of ink, impregnation of wood, and also in agricultural activities for the destruction of pests.
• Alum KCr(SO4)2 12H2O, KAl(SO4)2 12H2O, etc. are used in the production of paints and the leather industry (tanning).
• Many of you know copper sulfate CuSO4 5H2O firsthand. It is an active assistant in agriculture in the fight against plant diseases and pests - aqueous solution CuSO4 · 5H2O is treated with grain and sprayed with plants. It is also used to prepare some mineral paints. And in everyday life it is used to remove mold from the walls.
• Aluminum sulfate - it is used in the pulp and paper industry.

Sulfuric acid in dilute form is used as an electrolyte in lead-acid batteries. In addition, it is used to produce detergents and fertilizers. But in most cases, it comes in the form of oleum - this is a solution of SO3 in H2SO4 (other oleum formulas can also be found).

Amazing fact! Oleum is more reactive than concentrated sulfuric acid, but despite this, it does not react with steel! It is for this reason that it is easier to transport than sulfuric acid itself.

The sphere of use of the “queen of acids” is truly large-scale, and it is difficult to tell about all the ways in which it is used in industry. It is also used as an emulsifier in the food industry, for water treatment, in the synthesis of explosives, and for many other purposes.

History of sulfuric acid

Who among us has never heard of blue vitriol? So, it was studied in antiquity, and in some works of the beginning of a new era, scientists discussed the origin of vitriol and their properties. Vitriol was studied by the Greek physician Dioscorides, the Roman explorer of nature Pliny the Elder, and in their writings they wrote about the ongoing experiments. For medical purposes, various vitriol substances were used by the ancient healer Ibn Sina. How vitriol was used in metallurgy, was said in the works of alchemists Ancient Greece Zosimas of Panopolis.

The first way to obtain sulfuric acid is the process of heating potassium alum, and there is information about this in the alchemical literature of the XIII century. At that time, the composition of alum and the essence of the process were not known to alchemists, but already in the 15th century, they began to engage in the chemical synthesis of sulfuric acid purposefully. The process was as follows: alchemists treated a mixture of sulfur and antimony (III) sulfide Sb2S3 by heating with nitric acid.

In medieval times in Europe, sulfuric acid was called "vitriol oil", but then the name changed to vitriol.

In the 17th century, Johann Glauber obtained sulfuric acid by burning potassium nitrate and native sulfur in the presence of water vapor. As a result of the oxidation of sulfur with nitrate, sulfur oxide was obtained, which reacted with water vapor, and as a result, an oily liquid was obtained. It was vitriol oil, and this name for sulfuric acid exists to this day.

The pharmacist from London, Ward Joshua, in the thirties of the XVIII century used this reaction for the industrial production of sulfuric acid, but in the Middle Ages its consumption was limited to a few tens of kilograms. The scope of use was narrow: for alchemical experiments, purification of precious metals and in the pharmaceutical business. Concentrated sulfuric acid was used in small quantities in the manufacture of special matches that contained bertolet salt.

In Russia, vitriol appeared only in the 17th century.

In Birmingham, England, John Roebuck adapted the above method for producing sulfuric acid in 1746 and launched production. At the same time, he used strong large lead-lined chambers, which were cheaper than glass containers.

In industry, this method held positions for almost 200 years, and 65% sulfuric acid was obtained in the chambers.

After a while, the English Glover and the French chemist Gay-Lussac improved the process itself, and sulfuric acid began to be obtained with a concentration of 78%. But such an acid was not suitable for the production, for example, of dyes.

In the early 19th century, new methods were discovered for oxidizing sulfur dioxide to sulfuric anhydride.

Initially, this was done using nitrogen oxides, and then platinum was used as a catalyst. These two methods of oxidizing sulfur dioxide have further improved. The oxidation of sulfur dioxide on platinum and other catalysts became known as the contact method. And the oxidation of this gas with nitrogen oxides was called the nitrous method for producing sulfuric acid.

British merchant acetic acid It was only in 1831 that Peregrine Philips patented an economical process for the production of sulfur oxide (VI) and concentrated sulfuric acid, and it is he who is today known to the world as a contact method for obtaining it.

The production of superphosphate began in 1864.

In the eighties of the nineteenth century in Europe, the production of sulfuric acid reached 1 million tons. The main producers were Germany and England, producing 72% of the total volume of sulfuric acid in the world.

Transportation of sulfuric acid is a labor-intensive and responsible undertaking.

Sulfuric acid is classified as hazardous chemical substances, and on contact with the skin causes severe burns. In addition, it can cause chemical poisoning of a person. If certain rules are not followed during transportation, then sulfuric acid, due to its explosive nature, can cause a lot of harm to both people and the environment.

Sulfuric acid has been assigned a hazard class 8 and transportation must be carried out by specially trained and trained professionals. An important condition for the delivery of sulfuric acid is compliance with specially developed Rules for the transport of dangerous goods.

Transportation by road is carried out according to the following rules:

1. For transportation, special containers are made of a special steel alloy that does not react with sulfuric acid or titanium. Such containers do not oxidize. Hazardous sulfuric acid is transported in special sulfuric acid chemical tanks. They differ in design and are selected during transportation depending on the type of sulfuric acid.
2. When transporting fuming acid, specialized isothermal thermos tanks are taken, in which the necessary temperature regime is maintained to preserve the chemical properties of the acid.
3. If ordinary acid is being transported, then a sulfuric acid tank is selected.
4. Transportation of sulfuric acid by road, such as fuming, anhydrous, concentrated, for batteries, glover, is carried out in special containers: tanks, barrels, containers.
5. Transportation of dangerous goods can only be carried out by drivers who have an ADR certificate in their hands.
6. Travel time has no restrictions, since during transportation it is necessary to strictly adhere to the permissible speed.
7. During transportation, a special route is built, which should run, bypassing crowded places and production facilities.
8. Transport must have special markings and danger signs.

Dangerous properties of sulfuric acid for humans

Sulfuric acid poses an increased risk to human body. Its toxic effect occurs not only by direct contact with the skin, but by inhalation of its vapors, when sulfur dioxide is released. The hazard applies to:

• respiratory system;
• Integuments;
• Mucous membranes.

Intoxication of the body can be enhanced by arsenic, which is often part of sulfuric acid.

Important! As you know, when acid comes into contact with the skin, severe burns occur. No less dangerous is poisoning with sulfuric acid vapors. A safe dose of sulfuric acid in the air is only 0.3 mg per 1 square meter.

If sulfuric acid gets on the mucous membranes or on the skin, a severe burn appears, which does not heal well. If the burn is impressive in scale, the victim develops a burn disease, which can even lead to death if qualified medical care is not provided in a timely manner.

Important! For an adult, the lethal dose of sulfuric acid is only 0.18 cm per 1 liter.

Of course, it is problematic to “experience for yourself” the toxic effect of acid in ordinary life. Most often, acid poisoning occurs due to neglect of industrial safety when working with a solution.

Mass poisoning with sulfuric acid vapor can occur due to technical problems in production or negligence, and a massive release into the atmosphere occurs. To prevent such situations, special services are working, the task of which is to control the functioning of production where hazardous acid is used.

What are the symptoms of sulfuric acid intoxication?

If the acid was ingested:

• Pain in the region of the digestive organs.
• Nausea and vomiting.
• Violation of the stool, as a result of severe intestinal disorders.
• Strong secretion of saliva.
• Due to the toxic effects on the kidneys, the urine becomes reddish.
• Swelling of the larynx and throat. There are wheezing, hoarseness. This may lead to lethal outcome from suffocation.
• Brown spots appear on the gums.
• The skin turns blue.

With a burn of the skin, there can be all the complications inherent in a burn disease.

When poisoning in pairs, the following picture is observed:

• Burn of the mucous membrane of the eyes.
• Nose bleed.
• Burns of the mucous membranes of the respiratory tract. In this case, the victim experiences a strong pain symptom.
• Swelling of the larynx with symptoms of suffocation (lack of oxygen, skin turns blue).
• If the poisoning is severe, then there may be nausea and vomiting.

It's important to know! Acid poisoning after ingestion is much more dangerous than intoxication from inhalation of vapors.

First aid and therapeutic procedures for damage by sulfuric acid

Proceed as follows when in contact with sulfuric acid:

• Call first ambulance. If the liquid got inside, then do a gastric lavage with warm water. After that, in small sips you will need to drink 100 grams of sunflower or olive oil. In addition, you should swallow a piece of ice, drink milk or burnt magnesia. This must be done to reduce the concentration of sulfuric acid and alleviate the human condition.
• If acid gets into the eyes, rinse them with running water, and then drip with a solution of dicaine and novocaine.
• If acid gets on the skin, the burned area should be washed well under running water and bandaged with soda. Rinse for about 10-15 minutes.
• In case of vapor poisoning, you need to go out into fresh air, and also rinse the affected mucous membranes with water as far as possible.

In a hospital setting, treatment will depend on the area of ​​the burn and the degree of poisoning. Anesthesia is carried out only with novocaine. In order to avoid the development of an infection in the affected area, a course of antibiotic therapy is selected for the patient.

In gastric bleeding, plasma is injected or blood is transfused. The source of bleeding can be removed surgically.

1. Sulfuric acid in its pure 100% form is found in nature. For example, in Italy, Sicily in the Dead Sea, you can see a unique phenomenon - sulfuric acid seeps right from the bottom! And this is what happens: pyrite from earth's crust serves in this case as a raw material for its formation. This place is also called the Lake of Death, and even insects are afraid to fly up to it!
2. After large volcanic eruptions, drops of sulfuric acid can often be found in the earth's atmosphere, and in such cases the "culprit" can bring Negative consequences to the environment and cause serious climate change.
3. Sulfuric acid is an active water absorber, so it is used as a gas dryer. In the old days, in order to prevent windows from fogging up in the rooms, this acid was poured into jars and placed between the panes of window openings.
4. Sulfuric acid is the main cause of acid rain. main reason Acid rain is air pollution with sulfur dioxide, and when dissolved in water, it forms sulfuric acid. In turn, sulfur dioxide is emitted when fossil fuels are burned. In acid rain studied for last years, increased content nitric acid. The reason for this phenomenon is the reduction of sulfur dioxide emissions. Despite this fact, sulfuric acid remains the main cause of acid rain.

We offer you a video selection of interesting experiments with sulfuric acid.

Consider the reaction of sulfuric acid when it is poured into sugar. In the first seconds of sulfuric acid entering the flask with sugar, the mixture darkens. After a few seconds, the substance turns black. The most interesting thing happens next. The mass begins to grow rapidly and climb out of the flask. At the output, we get a proud substance, similar to porous charcoal, exceeding the original volume by 3-4 times.

The author of the video suggests comparing the reaction of Coca-Cola with hydrochloric acid and sulfuric acid. When mixing Coca-Cola with hydrochloric acid, no visual changes are observed, but when mixed with sulfuric acid, Coca-Cola begins to boil.

An interesting interaction can be observed when sulfuric acid gets on toilet paper. Toilet paper is made from cellulose. When acid enters, cellulose molecules instantly break down with the release of free carbon. Similar charring can be observed when acid gets on the wood.

I add a small piece of potassium to a flask with concentrated acid. In the first second, smoke is released, after which the metal instantly flares up, lights up and explodes, cutting into pieces.

In the next experiment, when sulfuric acid hits a match, it flares up. In the second part of the experiment, aluminum foil is immersed with acetone and a match inside. There is an instantaneous heating of the foil with the release of a huge amount of smoke and its complete dissolution.

An interesting effect is observed when baking soda is added to sulfuric acid. Soda instantly turns yellow. The reaction proceeds with rapid boiling and an increase in volume.

We categorically do not advise to carry out all the above experiments at home. Sulfuric acid is a very corrosive and toxic substance. Such experiments must be carried out in special rooms that are equipped with forced ventilation. The gases released in reactions with sulfuric acid are highly toxic and can cause damage to the respiratory tract and poison the body. In addition, such experiments are carried out in personal protective equipment for the skin and respiratory organs. Take care of yourself!