Hydrochloric acid(hydrochloric acid) - an aqueous solution of hydrogen chloride HCl, is a clear, colorless liquid with a pungent odor of hydrogen chloride. Technical acid has a yellowish-green color due to impurities of chlorine and iron salts. The maximum concentration of hydrochloric acid is about 36% HCl; such a solution has a density of 1.18 g/cm3. Concentrated acid "smokes" in air, since the escaping gaseous HCl forms tiny droplets of hydrochloric acid with water vapor.

Hydrochloric acid is not flammable, not explosive. It is one of the strongest acids, dissolves (with the release of hydrogen and the formation of salts - chlorides) all metals in the series of voltages up to hydrogen. Chlorides are also formed during the interaction of hydrochloric acid with metal oxides and hydroxides. With strong oxidizing agents, it behaves like a reducing agent.

Salts of hydrochloric acid - chlorides, with the exception of AgCl, Hg2Cl2, are highly soluble in water. Glass, ceramics, porcelain, graphite, fluoroplast are resistant to it.

Hydrochloric acid is obtained by dissolving hydrogen chloride in water, which is synthesized either directly from hydrogen and chlorine or obtained by the action of sulfuric acid on sodium chloride.

Produced technical hydrochloric acid has a strength of at least 31% HCl (synthetic) and 27.5% HCl (from NaCl). Commercial acid is called concentrated if it contains 24% or more HCl, if the HCl content is less, then the acid is called dilute.

Hydrochloric acid is used to obtain chlorides of various metals, organic intermediates and synthetic dyes, acetic acid, activated carbon, various adhesives, hydrolytic alcohol, and in electroforming. It is used for etching metals, for cleaning various vessels, casing pipes of boreholes from carbonates, oxides and other sediments and contaminants. In metallurgy, ores are treated with acid, in the leather industry - leather before tanning and dyeing. Hydrochloric acid is used in the textile, food industry, medicine, etc.

Hydrochloric acid plays an important role in the processes of digestion, it is an integral part of gastric juice. Diluted hydrochloric acid is prescribed orally mainly for diseases associated with insufficient acidity of gastric juice.

Hydrochloric acid is transported in glass bottles or gummed (coated with a layer of rubber) metal vessels, as well as in plastic containers.

Hydrochloric acid very dangerous for human health. Causes severe burns on contact with skin. Eye contact is especially dangerous.

If hydrochloric acid gets on the skin, it must be immediately washed off with a plentiful stream of water.

The fog and vapors of hydrogen chloride formed when interacting with air are very dangerous. concentrated acid. They irritate mucous membranes and the respiratory tract. Prolonged work in an atmosphere of HCl causes catarrh of the respiratory tract, tooth decay, clouding of the cornea of ​​​​the eyes, ulceration of the nasal mucosa, and gastrointestinal disorders.
Acute poisoning is accompanied by hoarseness, suffocation, runny nose, cough.

In the event of a leak or spill, hydrochloric acid can cause significant damage environment . Firstly, this leads to the release of vapors of the substance into the atmospheric air in quantities exceeding sanitary and hygienic standards, which can lead to the poisoning of all living things, as well as the appearance of acid precipitation, which can lead to a change chemical properties soil and water.

Secondly, it can seep into groundwater, resulting in pollution of inland waters.
Where the water in rivers and lakes has become quite acidic (pH less than 5), fish disappear. When trophic chains are disturbed, the number of aquatic animal species, algae and bacteria is reduced.

In cities, acid precipitation accelerates the destruction of marble and concrete structures, monuments and sculptures. Hydrochloric acid corrodes metals when it comes in contact with metals, and reacts with substances such as bleach, manganese dioxide, or potassium permanganate to form toxic chlorine gas.

In the event of a spill, hydrochloric acid is washed off surfaces with plenty of water or an alkaline solution that neutralizes the acid.

The material was prepared on the basis of information from open sources

Hydrochloric acid

Chemical properties

Hydrochloric acid, hydrogen chloride or hydrochloric acid - solution Hcl in water. According to Wikipedia, the substance belongs to the group of inorganic strong monobasic to-t. The full name of the compound in Latin: hydrochloric acid.

Formula of hydrochloric acid in chemistry: HCl. In a molecule, hydrogen atoms combine with halogen atoms - Cl. If we consider the electronic configuration of these molecules, it can be noted that the compounds take part in the formation of molecular orbitals 1s-hydrogen orbitals and both 3s And 3p-orbitals of an atom Cl. In the chemical formula of hydrochloric acid 1s-, 3s- And 3r-atomic orbitals overlap and form 1, 2, 3 orbitals. Wherein 3s-orbital is not binding. There is a shift of the electron density to the atom Cl and the polarity of the molecule decreases, but the binding energy of molecular orbitals increases (if we consider it along with other hydrogen halides ).

Physical properties of hydrogen chloride. It is a clear, colorless liquid that smokes when exposed to air. Molar mass of a chemical compound = 36.6 grams per mole. Under standard conditions, at an air temperature of 20 degrees Celsius, the maximum concentration of a substance is 38% by weight. The density of concentrated hydrochloric acid in this kind of solution is 1.19 g/cm³. In general, physical properties and characteristics such as density, molarity, viscosity, heat capacity, boiling point and pH, strongly depend on the concentration of the solution. These values ​​are discussed in more detail in the table of densities. For example, the density of Hydrochloric Acid 10% = 1.048 kg per liter. When solidified, the substance forms crystalline hydrates different compositions.

Chemical properties of hydrochloric acid. What does hydrochloric acid react with? The substance interacts with metals that stand in front of hydrogen in a series of electrochemical potentials (iron, magnesium, zinc, and others). In this case, salts are formed and gaseous H. Lead, copper, gold, silver and other metals to the right of hydrogen do not react with hydrochloric acid. The substance reacts with metal oxides producing water and a soluble salt. Sodium hydroxide under the action of to-you forms and water. The neutralization reaction is characteristic of this compound.

Dilute Hydrochloric Acid reacts with metal salts, which are formed by weaker acids. For example, propionic acid weaker than salt. The substance does not react with stronger acids. And sodium carbonate will form after reaction with HCl chloride, carbon monoxide and water.

For a chemical compound, reactions with strong oxidizing agents are characteristic, with manganese dioxide , potassium permanganate : 2KMnO4 + 16HCl = 5Cl2 + 2MnCl2 + 2KCl + 8H2O. The substance reacts with ammonia , which produces thick white smoke, which consists of very fine crystals of ammonium chloride. The mineral pyrolusite also reacts with hydrochloric acid, as it contains manganese dioxide : MnO2+4HCl=Cl2+MnO2+2H2O(oxidation reaction).

There is a qualitative reaction to hydrochloric acid and its salts. When a substance interacts with silver nitrate a white precipitate silver chloride and formed nitric acid . Interaction reaction equation methylamine with hydrogen chloride looks like in the following way: HCl + CH3NH2 = (CH3NH3)Cl.

A substance reacts with a weak base aniline . After dissolving aniline in water, hydrochloric acid is added to the mixture. As a result, the base dissolves and forms aniline hydrochloride (phenylammonium chloride ): (С6Н5NH3)Cl. The reaction of interaction of aluminum carbide with hydrochloric acid: Al4C3+12HCL=3CH4+4AlCl3. Reaction equation potassium carbonate with which it looks like this: K2CO3 + 2HCl = 2KCl + H2O + CO2.

Getting hydrochloric acid

To obtain synthetic hydrochloric acid, hydrogen is burned in chlorine, and then the resulting gaseous hydrogen chloride is dissolved in water. It is also common to produce a reagent from off-gases, which are formed as by-products during the chlorination of hydrocarbons (off-gas Hydrochloric Acid). In the production of this chemical compound, GOST 3118 77- for reagents and GOST 857 95– for technical synthetic hydrochloric acid.

In the laboratory, you can use a long-standing method in which table salt is exposed to concentrated sulfuric acid. Also, the agent can be obtained using the hydrolysis reaction aluminum chloride or magnesium . During the reaction, oxychlorides variable composition. To determine the concentration of a substance, standard titers are used, which are available in sealed ampoules, so that later it is possible to obtain a standard solution of a known concentration and use it to determine the quality of another titrant.

The substance has a fairly wide scope:

• it is used in hydrometallurgy, pickling and pickling;
• when cleaning metals during tinning and soldering;
• as a reagent for obtaining manganese chloride , zinc, iron and other metals;
• in the manufacture of mixtures with surfactants for cleaning metal and ceramic products from infection and dirt (inhibited hydrochloric acid is used);
• as an acidity regulator E507 in the food industry, as part of soda water;
• in medicine with insufficient acidity of gastric juice.

This chemical compound has a high hazard class - 2 (according to GOST 12L.005). When working with acid, special skin and eye protection. Sufficiently caustic substance in contact with the skin or inhalation causes chemical burns. To neutralize it, alkali solutions are used, most often baking soda. Hydrogen chloride vapor forms a caustic mist with water molecules in the air, which irritates the respiratory tract and eyes. If the substance reacts with bleach, potassium permanganate and other oxidizing agents, then a toxic gas, chlorine, is formed. On the territory of the Russian Federation, the circulation of Hydrochloric Acid with a concentration of more than 15% is limited.

pharmachologic effect

Increases the acidity of gastric juice.

Pharmacodynamics and pharmacokinetics

What is gastric acidity? This is a characteristic of the concentration of hydrochloric acid in the stomach. Acidity is expressed in pH. Normally, acid should be produced in the composition of gastric juice and take an active part in the processes of digestion. Formula of hydrochloric acid: HCl. It is produced by parietal cells located in the fundic glands, with the participation of H+/K+-ATPase . These cells line the fundus and body of the stomach. The acidity of gastric juice itself is variable and depends on the number of parietal cells and the intensity of the processes of neutralization of the substance by the alkaline components of gastric juice. Concentration produced to - you are stable and equal to 160 mmol/l. A healthy person should normally produce no more than 7 and at least 5 mmol of a substance per hour.

With insufficient or excessive production of Hydrochloric Acid, diseases of the digestive tract occur, the ability to absorb certain microelements, such as iron, deteriorates. The drug stimulates the secretion of gastric juice, reduces pH. Activates pepsinogen , converts it into an active enzyme pepsin . The substance has a beneficial effect on the acid reflex of the stomach, slows down the transition of incompletely digested food into the intestines. The processes of fermentation of the contents of the digestive tract slow down, pain and belching disappear, iron is better absorbed.

After oral administration, the drug is partially metabolized by saliva and gastric mucus, the contents of the duodenum 12. The unbound substance penetrates into the duodenum, where it is completely neutralized by its alkaline contents.

Indications for use

The substance is part of synthetic detergents, a concentrate for rinsing the oral cavity for the care of contact lenses. Diluted Hydrochloric Acid is prescribed for diseases of the stomach, accompanied by low acidity, with hypochromic anemia in combination with iron preparations.

Contraindications

The medicine should not be used for allergies on a synthetic substance, with diseases of the digestive tract associated with high acidity, with.

Side effects

Concentrated Hydrochloric Acid can cause severe burns if it comes into contact with the skin, eyes or respiratory tract. As part of various lek. drugs use a diluted substance, with prolonged use of large dosages, a deterioration in the condition of tooth enamel may occur.

Instructions for use (Method and dosage)

Hydrochloric acid is used in accordance with the instructions.

Inside the medicine is prescribed, previously dissolved in water. Usually use 10-15 drops of the drug in half a glass of liquid. The medicine is taken with meals, 2-4 times a day. The maximum single dosage is 2 ml (about 40 drops). Daily dose - 6 ml (120 drops).

Overdose

Cases of overdose are not described. With uncontrolled intake of the substance inside in large quantities, ulcers and erosions occur in the digestive tract. You should seek help from a doctor.

Interaction

The substance is often used in combination with pepsin and other medicines. drugs. The chemical compound in the digestive tract interacts with bases and some substances (see chemical properties).

special instructions

When treating with hydrochloric acid preparations, it is necessary to strictly adhere to the recommendations in the instructions.

Preparations containing (Analogues)

Coincidence in the ATX code of the 4th level:

For industrial purposes, inhibited hydrochloric acid (22-25%) is used. For medical purposes, the solution is used: Hydrochloric acid diluted . The substance is also contained in a concentrate for rinsing the mouth. Parontal , in soft contact lens care solution Biotru .

Hydrochloric acid coming from the plant can have different concentrations, so it is necessary to calculate the amount of water and acid using table 6.2

Table 6.2

denseHClat 15 about С, kg/m 3	masses. shareHCl, %	weight fractionHClkg/l	denseHClat 15 about С, kg/m 3	masses. shareHCl, %	weight fractionHClkg/l

The amount of commercial acid in volume units required to obtain 1 m 3 of a working solution of a given concentration is determined by the formula:

V T \u003d n (r Z - 1000) / (r T - 1000) (5.2)

where n is the number of cubic meters of solution;

V T - the volume of commercial acid, m 3;

r t - commercial acid density, kg/m 3 ;

r З - the given density of the finished solution, kg / m 3, which is taken from table 6.2, based on the percentage mass content of HCl in the solution.

Example. Prepare 35 m 3 of a 12% HCl solution, if the density of the commercial acid is 1150 kg / m 3. According to table 6.2, we find that the density of a 12% HCl solution is 1060 kg / m 3. Then

V T \u003d 35 (1060 - 1000) / (1150 - 1000) \u003d 14 m 3

The volume of water for preparing the solution is 35 - 14 \u003d 21 m 3. Let's check the calculation results:

r W \u003d (14 × 1150 + 21 × 1000) / 35 \u003d 1060 kg / m 3

1. Equipment for acid treatment of wells

To treat the formation with acid, a set of equipment is used, which includes fittings for the wellhead (1AU - 700, 2AU - 700), a pump unit for injecting acid into the well, a tank truck for transporting acid and chemicals, a manifold for connecting the tank truck with the pump unit and with mouth fittings.

During hydrochloric acid treatment, the concentration of acid in the solution is 8-20%, depending on the treated rocks. If the concentration of HCl is higher than the recommended one, the pipes of the wellhead and downhole equipment are destroyed, and if it is lower, the efficiency of the treatment of the bottomhole zone decreases.

To protect pipes, tanks, pumps, pipelines, wellhead and downhole equipment from the corrosive effects of acid, inhibitors are added to the solution: formalin (0.6%), unicol (0.3 - 0.5%), reagent I-1-A ( 0.4%) and catapin A (0.1%).

To prevent the precipitation of iron oxides that clog the pores of the formation, stabilizers are used, which are used as acetic (0.8-1.6%) and hydrofluoric (1-2%) acids from the volume of diluted hydrochloric acid.

The HCl solution is prepared as follows: a calculated volume of water is poured into the container, an inhibitor is added to it, then a stabilizer and a reaction retarder - a DS preparation in an amount of 1 - 1.5% of the volume of the acid solution. After thorough mixing of the solution, the calculated volume of concentrated HCl is added last.

The fields use acid injection into the formation under pressure, acid baths to clean the bottom surface from contaminating deposits (cement, mud, resins, paraffin), as well as injection of a hot acid solution, which is heated due to the exothermic reaction between HCl and magnesium.

To transport the solution of inhibited HCl and inject it into the reservoirs, special units Azinmash - 30A, automatic transmission - 500, KP - 6.5 are used. The Azinmash - 30A unit is mounted on the chassis of a KrAZ - 257 vehicle. The unit consists of a three-plunger horizontal single-acting pump 5NK - 500 driven by a propulsion engine through a power take-off, a manifold, rubber-lined tanks main (6-10 m 3) and on a trailer (6 m 3).

HYDROCHLORIC ACID (hydrochloric acid) - a strong monobasic acid, a solution of hydrogen chloride HCl in water, is one of the most important components of gastric juice; in medicine it is used as a medicine for insufficiency of the secretory function of the stomach. S. to. is one of the most commonly used chem. reagents used in biochemical, sanitary-hygienic and clinical diagnostic laboratories. In dentistry, 10% S. solution is used to whiten teeth with fluorosis (see Teeth Whitening). S. to. is used to obtain alcohol, glucose, sugar, organic dyes, chlorides, gelatin and glue, in the farm. industry, in tanning and dyeing leather, saponification of fats, in the production of activated carbon, dyeing of fabrics, etching and soldering of metals, in hydrometallurgical processes for cleaning boreholes from deposits of carbonates, oxides and other sediments, in electroforming, etc.

S. to. for people in contact with it during the production process, it represents a significant occupational hazard.

S. to. was known as early as the 15th century. Her discovery is attributed to him. Alchemist Valentine. For a long time it was believed that S. to. is an oxygen compound of a hypothetical chemical. element muria (hence one of its names - acidum muriaticum). Chem. The structure of S. to. was finally established only in the first half of the 19th century. Davy (N. Davy) and J. Gay-Lussac.

In nature, free S. practically does not occur, however, its salts sodium chloride (see Table salt), potassium chloride (see), magnesium chloride (see), calcium chloride (see), etc. are very widespread.

Hydrogen chloride HCl under normal conditions is a colorless gas with a specific pungent odor; when released into moist air, it strongly "smokes", forming the smallest droplets of aerosol S. to. Hydrogen chloride is toxic. Weight (mass) of 1 liter of gas at 0° and 760 mm Hg. Art. equal to 1.6391 g, air density 1.268. Liquid hydrogen chloride boils at -84.8° (760 mmHg) and solidifies at -114.2°. In water, hydrogen chloride dissolves well with the release of heat and the formation of S. to .; its solubility in water (g/100 g H2O): 82.3 (0°), 72.1 (20°), 67.3 (30°), 63.3 (40°), 59.6 (50° ), 56.1 (60°).

Page to. represents colorless transparent liquid with a sharp smell of hydrogen chloride; impurities of iron, chlorine, or other substances stain S. to. in a yellowish-greenish color.

Approximate value of S.'s concentration to. in percent can be found if beats. S.'s weight to. reduce by one and multiply the resulting number by 200; e.g., if weight S. to. 1.1341, then its concentration is 26.8%, i.e. (1.1341 - 1) 200.

S. to. chemically very active. It dissolves with the release of hydrogen all metals that have a negative normal potential (see Physico-chemical potentials), converts many metal oxides and hydroxides into chlorides, and releases free acids from salts such as phosphates, silicates, borates, etc.

In a mixture with nitric acid (3:1), the so-called. aqua regia, S. to. reacts with gold, platinum and other chemically inert metals, forming complex ions (AuC14, PtCl6, etc.). Under the influence of oxidizers S. to. is oxidized to chlorine (see).

S. to. reacts with many organic substances, for example, proteins, carbohydrates, etc. Some aromatic amines, natural and synthetic alkaloids, and other basic organic compounds form salts with S. to. Paper, cotton, linen, and many artificial fibers are destroyed by S. to.

The main method for producing hydrogen chloride is synthesis from chlorine and hydrogen. The synthesis of hydrogen chloride proceeds in accordance with the reaction H2 + 2C1-^2HCl + 44.126 kcal. Other ways to produce hydrogen chloride are chlorination organic compounds, dehydrochlorination of organic chlorine derivatives and hydrolysis of certain inorganic compounds with the elimination of hydrogen chloride. Less often, in the lab. practice, they use the old method of producing hydrogen chloride by the interaction of common salt with sulfuric acid.

A characteristic reaction to S. to. and its salts is the formation of a white cheesy precipitate of silver chloride AgCl, soluble in excess water solution ammonia:

HCl + AgN03 - AgCl + HN03; AgCl + 2NH4OH - [Ag (NHs)2] Cl + + 2H20.

Store S. to. in glassware with ground stoppers in a cool room.

In 1897, IP Pavlov found that the parietal cells of the gastric glands of humans and other mammals secrete S. to a constant concentration. It is assumed that the mechanism of S.'s secretion to. consists in the transfer of H+ ions by a specific carrier to the outer surface of the apical membrane of the intracellular tubules of parietal cells and in their entry after additional conversion into gastric juice (see). C1~ ions from the blood penetrate into the parietal cell while simultaneously transferring the bicarbonate ion HCO2 in the opposite direction. Due to this, C1 ~ ions enter the parietal cell against the concentration gradient and from it into the gastric juice. The parietal cells secrete a solution

Page to., concentration to-rogo makes apprx. 160 mmol!l.

Bibliography: Volfkovich S. I., Egorov A. P. and Epshtein D. A. General chemical technology, vol. 1, p. 491 and others, M.-L., 1952; Harmful substances in industry, ed. N. V. Lazarev and I. D. Gadaskina, vol. 3, p. 41, L., 1977; Nekrasov B.V. Fundamentals of General Chemistry, vol. 1 - 2, M., 1973; Emergency care for acute poisoning, Handbook of toxicology, ed. S. N. Golikova, p. 197, Moscow, 1977; Fundamentals of forensic medicine, ed. N. V. Popova, p. 380, M.-L., 1938; Radbil O. S. Pharmacological bases for the treatment of diseases of the digestive system, p. 232, M., 1976; Rem and G. Course inorganic chemistry, per. from German, vol. 1, p. 844, M., 1963; Guidelines for forensic medical examination of poisonings, ed. R. V. Berezhnoy and others, p. 63, M., 1980.

N. G. Budkovskaya; N. V. Korobov (farm.), A. F. Rubtsov (court.).

Structural formula

True, empirical, or gross formula: HCl

Chemical composition of hydrochloric acid

Molecular weight: 36.461

Hydrochloric acid(also hydrochloric, hydrochloric acid, hydrogen chloride) - a solution of hydrogen chloride (HCl) in water, a strong monobasic acid. Colorless, transparent, caustic liquid, "fuming" in air (technical hydrochloric acid is yellowish due to impurities of iron, chlorine, etc.). At a concentration of about 0.5%, it is present in the human stomach. The maximum concentration at 20 °C is 38% by weight, the density of such a solution is 1.19 g/cm³. Molar mass 36.46 g/mol. Salts of hydrochloric acid are called chlorides.

Physical Properties

The physical properties of hydrochloric acid are highly dependent on the concentration of dissolved hydrogen chloride. When solidified, it gives crystalline hydrates of the compositions HCl H 2 O, HCl 2H 2 O, HCl 3H 2 O, HCl 6H 2 O.

Chemical properties

• Interaction with metals standing in a series of electrochemical potentials up to hydrogen, with the formation of a salt and the release of gaseous hydrogen.
• Interaction with metal oxides to form a soluble salt and water.
• Interaction with metal hydroxides to form a soluble salt and water (neutralization reaction).
• Interaction with metal salts formed by weaker acids, such as carbonic.
• Interaction with strong oxidizing agents (potassium permanganate, manganese dioxide) with the release of gaseous chlorine.
• Interaction with ammonia with the formation of thick white smoke, consisting of the smallest crystals of ammonium chloride.
• A qualitative reaction to hydrochloric acid and its salts is its interaction with silver nitrate, which forms a curd precipitate of silver chloride, insoluble in nitric acid.

Receipt

Hydrochloric acid is produced by dissolving hydrogen chloride gas in water. Hydrogen chloride is obtained by burning hydrogen in chlorine, the acid obtained in this way is called synthetic. Hydrochloric acid is also obtained from off-gases - by-product gases generated during various processes, for example, during the chlorination of hydrocarbons. The hydrogen chloride contained in these gases is called off-gas, and the acid thus obtained is called off-gas. In recent decades, the share of waste hydrochloric acid in the production volume has been gradually increasing, displacing the acid obtained by burning hydrogen in chlorine. But hydrochloric acid obtained by burning hydrogen in chlorine contains fewer impurities and is used if necessary. high purity. In laboratory conditions, a method developed by alchemists is used, which consists in the action of concentrated sulfuric acid on table salt. At temperatures above 550 °C and an excess of table salt, interaction is possible. It is possible to obtain by hydrolysis of chlorides of magnesium, aluminum (hydrated salt is heated). These reactions may not go to completion with the formation of basic chlorides (oxychlorides) of variable composition, for example. Hydrogen chloride is highly soluble in water. So, at 0 °C, 1 volume of water can absorb 507 volumes of HCl, which corresponds to an acid concentration of 45%. However, at room temperature, the solubility of HCl is lower, so 36% hydrochloric acid is usually used in practice.

Application

Industry

• It is used in hydrometallurgy and electroforming (etching, pickling), for cleaning the surface of metals during soldering and tinning, for obtaining chlorides of zinc, manganese, iron, and other metals. In a mixture with surfactants, it is used to clean ceramic and metal products (inhibited acid is needed here) from contamination and disinfection.
• It is registered in the food industry as an acidity regulator (food additive E507). It is used to make seltzer (soda) water.

The medicine

• A natural component of human gastric juice. At a concentration of 0.3-0.5%, usually mixed with the enzyme pepsin, it is administered orally with insufficient acidity.

Features of circulation

Highly concentrated hydrochloric acid is a corrosive substance that causes severe chemical burns if it comes into contact with the skin. Eye contact is especially dangerous. To neutralize burns, a weak alkali solution, usually baking soda, is used. When opening vessels with concentrated hydrochloric acid, hydrogen chloride vapor, attracting moisture from the air, forms a fog that irritates the eyes and respiratory tract of a person. Reacts with strong oxidizing agents (chlorine, manganese dioxide, potassium permanganate) to form toxic chlorine gas. In the Russian Federation, the circulation of hydrochloric acid with a concentration of 15% or more is limited.