Hydrochloric acid application. Hydrochloric acid

1.2679; G crnt 51.4°C, p crit 8.258 MPa, d crit 0.42 g/cm 3 ; -92.31 kJ / , D H pl 1.9924 kJ / (-114.22 ° C), D H test 16.1421 kJ / (-8.05 ° C); 186.79 J / (mol K); (Pa): 133.32 10 -6 (-200.7 ° C), 2.775 10 3 (-130.15 ° C), 10.0 10 4 (-85.1 ° C), 74, 0 10 4 (-40 ° C), 24.95 10 5 (O ° C), 76.9 10 5 (50 ° C); temperature dependence equation lgp (kPa) = -905.53 / T + 1.75lgT- -500.77 10 -5 T + 3.78229 (160-260 K); coefficient 0.00787; g 23 mN/cm (-155°C); r 0.29 10 7 Ohm m (-85°C), 0.59 10 7 (-114.22°C). See also table. one.

R-value of HC1 at 25 °C and 0.1 MPa (mol.%): in pentane-0.47, hexane-1.12, heptane-1.47, octane-1.63. The p-value of HC1 in alkyl and aryl halides is low, for example. 0.07 / for C 4 H 9 C1. P-value in the range from -20 to 60 ° C decreases in the series dichloroethane-tri-chloroethane-tetrachloroethane-trichlorethylene. The p-value at 10°C in the series is approximately 1 / , in ethers carbon kit 0.6 / , in carbonic acid 0.2 / . In stable R 2 O · НCl are formed. The p-value of HC1 is subject to and is for KCl 2.51 10 -4 (800 ° C), 1.75 10 -4 / (900 ° C), for NaCl 1.90 10 -4 / (900 ° WITH).

Salt to-ta. HCl in water is highly exothermic. process, for infinitely razb. water solution D H 0 Hcl -69.9 kJ / , Cl -- 167.080 kJ/; HC1 is fully ionized. The solubility of HC1 in depends on the t-ry (Table 2) and the partial HC1 in the gas mixture. Density of salt dec. and h at 20 °C are presented in Table. 3 and 4. With an increase in t-ry h hydrochloric decreases, for example: for 23.05% hydrochloric at 25 ° C h 1364 mPa s, at 35 ° C 1.170 mPa s. hydrochloric containing h per 1 HC1, is [kJ/(kg K)]: 3.136 (n = 10), 3.580 (n = 20), 3.902 (n = 50), 4.036 (n = 100), 4.061 (n = 200).

HCl forms c (Table 5). In the HCl-water system, there are three eutectic. points: - 74.7 ° C (23.0% by mass of HCl); -73.0°C (26.5% HCl); -87.5°C (24.8% HC1, metastable phase). HCl nH 2 O are known, where n = 8.6 (mp. -40 ° С), 4. 3 (mp. -24.4 ° С), 2 (mp. -17.7 °С) and 1 (mp. -15.35°С). crystallizes from 10% hydrochloric acid at -20, from 15% hydrochloric acid at -30, from 20% hydrochloric acid at -60 and from 24% hydrochloric acid at -80°C. The p-value of halides decreases with increasing HCl in hydrochloric acid, which is used for them.

Chemical properties. Pure dry HCl begins to dissociate above 1500°C, it is chemically passive. Mn. , C, S, P not interact. even with liquid HCl. C, reacts above 650 ° C, with Si, Ge and B-in are present. AlCl 3, with transition metals - at 300 ° C and above. O 2 and HNO 3 are oxidized to Cl 2, with SO 3 gives C1SO 3 H. O p-tions with org. connections see .

With hydrochloric acid is chemically very active. Dissolves with the release of H 2 all having negative. ,with me. and forms, allocates free. to-you from such as, etc.

Receipt. In the industry, Hcl get a trace. ways-sulfate, synthetic. and from off-gases (by-products) of a number of processes. The first two methods lose their meaning. So, in the USA in 1965 the share of off-gas salt was 77.6% in the total volume of production, and in 1982-94%.

The production of hydrochloric (reactive, obtained by the sulphate method, synthetic, off-gas) consists in obtaining HCl with the last. his . Depending on the method of heat removal (reaches 72.8 kJ/), the processes are divided into isothermal, adiabatic. and combined.

The sulfate method is based on the interaction. NaCl with conc. H 2 SO 4 at 500-550 ° C. reaction contain from 50-65% HCl (muffle) to 5% HCl (reactor with). It is proposed to replace H 2 SO 4 with a mixture of SO 2 and O 2 (process temperature approx. 540 ° C, cat.-Fe 2 O 3).

The direct synthesis of HCl is based on the chain p-tion: H 2 + Cl 2 2HCl + 184.7 kJ K p is calculated according to the equation: lgK p \u003d 9554 / T- 0.5331g T + 2.42.

R-tion is initiated by light, moisture, solid porous (, porous Pt) and some miners. in-you ( , ). Synthesis is carried out with an excess of H 2 (5-10%) in combustion chambers made of steel, refractory bricks. Naib. modern HCl pollution prevention material - graphite impregnated with phenol-formald. resins. To prevent an explosive nature, they are mixed directly in the flame of the burner. To the top. the zone of the combustion chambers is installed to cool the reaction. up to 150-160°С. The power of modern graphite reaches 65 tons / day (in terms of 35% hydrochloric acid). In case of H 2 deficiency, decomp. process modifications; for example, a mixture of Cl 2 with water is passed through a layer of porous incandescent:

2Cl 2 + 2H 2 O + C: 4HCl + CO 2 + 288.9 kJ

The temperature of the process (1000-1600 ° C) depends on the type and presence of impurities in it, which are (eg, Fe 2 O 3). It is promising to use a mixture of CO with:

CO + H 2 O + Cl 2: 2HCl + CO 2

More than 90% of hydrochloric acid in developed countries is obtained from off-gas HCl, which is formed during and dehydrochlorination of org. compounds, chlororg. waste, obtaining potassium non-chlorinated. etc. Abgazes contain decomp. quantity of HC1, inert impurities (N 2, H 2, CH 4), slightly soluble in org. in-va (, ), water-soluble in-va (acetic acid,), acidic impurities (Cl 2, HF, O 2) and. The use of isothermal it is expedient at a low content of HC1 in exhaust gases (but with the content of inert impurities less than 40%). Naib. promising film, allowing you to extract from the original exhaust gas from 65 to 85% HCl.

Naib. adiabatic schemes are widely used. . Abgases are introduced into the lower. part, and (or dilute hydrochloric) - countercurrent to the top. Salt is heated to t-ry due to the heat of HCl. The change in t-ry and Hcl is given in fig. 1. T-ra is determined by the temperature of the corresponding one (max. t-ra-t. boiling of the azeotropic mixture is approx. 110 ° C).

On fig. 2 shows a typical adiabatic scheme. HCl from off-gases generated during (eg, production). Hcl is absorbed in 1, and the remains of sparingly soluble in org. in-in is separated from after in apparatus 2, further cleaned in tail column 4 and separators 3, 5 and commercial hydrochloric acid is obtained.

Rice. 1. Distribution scheme t-r (curve 1) and

Hydrochloric acid- this is one of the most powerful and dangerous substances for humans in the list of AHOV. However, it is surprising that it exists in the body of every person: hydrochloric acid is an integral part gastric juice and plays an important role in the digestive process. In the amount of 0.2%, it promotes the transition of food masses from the stomach to duodenum and neutralizes microbes that enter the stomach from external environment. It also activates the enzyme pepsinogen, is involved in the formation of secretin and some other hormones that stimulate the activity of the pancreas. For this purpose, it is used in medicine, prescribing its solution to patients to increase the acidity of gastric juice. In general, hydrochloric acid has wide application in our life. For example, in heavy industry - to obtain chlorides of various metals, in textile industry- to obtain synthetic dyes; for the food industry, it is used to make acetic acid, for pharmaceutical - Activated carbon. It is also found in various adhesives and hydrolysis alcohol. It is used for etching metals, cleaning various vessels, casing pipes of boreholes from carbonates, oxides and other sediments and contaminants. In metallurgy, ores are treated with hydrochloric acid; in the leather industry, leather is treated before tanning and dyeing. Hydrochloric acid is transported in glass bottles or gummed (coated with a layer of rubber) metal vessels, as well as in plastic containers.

What is it as a chemical substance?

Hydrochloric acid, or hydrochloric acid, is an aqueous solution of hydrogen chloride HCl, which is a clear, colorless liquid with a pungent odor of hydrogen chloride. The technical variety of 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 it "smokes" in air, since the escaping gaseous HCl forms tiny droplets of hydrochloric acid with water vapor.

Despite this characteristic, hydrochloric acid is neither flammable nor explosive when exposed to air. But at the same time, it is one of the strongest acids and 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 by the interaction of hydrochloric acid with metal oxides and hydroxides. With strong oxidizing agents, it behaves like a reducing agent.

Salts of hydrochloric acid are chlorides and, with the exception of AgCl, Hg2Cl2, are highly soluble in water. Materials such as glass, ceramics, porcelain, graphite, and fluoroplastic are resistant to hydrochloric acid.

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

Commercially available (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 an inorganic substance, monobasic acid, one of the strongest acids. Other names are also used: hydrogen chloride, hydrochloric acid, hydrochloric acid.

Properties

Acid in pure form is a colorless and odorless liquid. Technical acid usually contains impurities that give it a slightly yellowish tint. Hydrochloric acid is often referred to as "fuming" because it releases hydrogen chloride vapor, which reacts with atmospheric moisture to form an acid mist.

It dissolves very well in water. At room temperature, the maximum possible mass content of hydrogen chloride is 38%. An acid concentration greater than 24% is considered concentrated.

Hydrochloric acid actively reacts with metals, oxides, hydroxides, forming salts - chlorides. HCl interacts with salts of weaker acids; with strong oxidizing agents and ammonia.

To determine hydrochloric acid or chlorides, a reaction with silver nitrate AgNO3 is used, as a result of which a white cheesy precipitate precipitates.

Safety

The substance is very caustic, corrosive to skin, organic materials, metals and their oxides. In the air, it emits hydrogen chloride vapors, which cause suffocation, burns to the skin, mucous membranes of the eyes and nose, damage the respiratory system, and destroy teeth. Hydrochloric acid belongs to the substances of the 2nd degree of danger (highly dangerous), the MPC of the reagent in the air is 0.005 mg/l. It is possible to work with hydrogen chloride only in filtering gas masks and protective clothing, including rubber gloves, an apron, safety shoes.

If acid is spilled, it is washed off with large amounts of water or neutralized with alkaline solutions. Victims of acid should be taken out of the danger zone, rinse the skin and eyes with water or soda solution, call a doctor.

It is allowed to transport and store a chemical reagent in a glass, plastic container, as well as in a metal container, covered from the inside with a rubber layer. The container must be hermetically sealed.

Receipt

Commercially, hydrochloric acid is produced from hydrogen chloride (HCl) gas. Hydrogen chloride itself is produced in two main ways:
- exothermic reaction of chlorine and hydrogen - in this way a high purity reagent is obtained, for example, for the food industry and pharmaceuticals;
- from accompanying industrial gases - an acid based on such HCl is called off-gas.

It's curious

It is to hydrochloric acid that nature "entrusted" the process of splitting food in the body. The concentration of acid in the stomach is only 0.4%, but this is enough to digest a razor blade in a week!

The acid is produced by the cells of the stomach itself, which is protected from this aggressive substance by the mucous membrane. However, its surface is updated daily to repair damaged areas. In addition to participating in the process of digestion of food, acid also performs protective function, killing pathogens that enter the body through the stomach.

Application

- In medicine and pharmaceuticals - to restore the acidity of gastric juice in case of its insufficiency; with anemia to improve the absorption of iron-containing drugs.
- In the food industry, this is a food additive, acidity regulator E507, as well as an ingredient in seltzer (soda) water. Used in the manufacture of fructose, gelatin, citric acid.
- In the chemical industry - the basis for the production of chlorine, soda, sodium glutamate, metal chlorides, for example zinc chloride, manganese chloride, iron chloride; synthesis of organochlorine substances; catalyst in organic synthesis.
- Most of the hydrochloric acid produced in the world is used in metallurgy to clean workpieces from oxides. For these purposes, an inhibited technical acid is used, which contains special inhibitors (retarders) of the reaction, due to which the reagent dissolves oxides, but not the metal itself. Metals are also poisoned with hydrochloric acid; clean them before tinning, soldering, galvanizing.
— Treat the skin before tanning.
- In the mining industry, it is in demand for cleaning boreholes from deposits, for processing ores and rock formations.
— In laboratory practice, hydrochloric acid is used as a popular reagent for analytical studies, for cleaning vessels from hard-to-remove contaminants.
– It is used in the rubber, pulp and paper industry, in ferrous metallurgy; for cleaning boilers, pipes, equipment from complex deposits, scale, rust; for cleaning ceramic and metal products.

Hydrochloric acid is a solution of hydrogen chloride in water. Hydrogen chloride (HCl) under normal conditions is a colorless gas with a specific pungent odor. However, we are dealing with aqueous solutions, so we will focus only on them.

Hydrochloric acid is a colorless transparent solution with a pungent odor of hydrogen chloride. In the presence of impurities of iron, chlorine or other substances, the acid has a yellowish-green color. The density of a hydrochloric acid solution depends on the concentration of hydrogen chloride in it; some data is given in table 6.9.

Table 6.9. Density of hydrochloric acid solutions of various concentrations at 20°C.

From this table it can be seen that the dependence of the density of a hydrochloric acid solution on its concentration with an accuracy satisfactory for technical calculations can be described by the formula:

d = 1 + 0.5*(%) / 100

When dilute solutions boil, the HCl content in vapors is less than in solution, and when concentrated solutions boil, it is higher than in solution, which is reflected in the figure. rice. 6.12 equilibrium diagram. A constantly boiling mixture (azeotrope) at atmospheric pressure has a composition of 20.22% wt. HCl, boiling point 108.6°C.

Finally, another important advantage of hydrochloric acid is the almost complete independence of the time of its acquisition from the time of year. As seen from rice. No. 6.13, acid of industrial concentration (32-36%) freezes at temperatures that are practically unattainable for the European part of Russia (from -35 to -45 ° C), unlike sulfuric acid, which freezes at positive temperatures, which requires the introduction of a tank heating operation.

Hydrochloric acid does not have the disadvantages of sulfuric acid.

First, ferric chloride has an increased solubility in hydrochloric acid solution. (Fig. 6.14), which allows you to raise the concentration of ferric chloride in the solution to a value of 140 g/l and even more; the risk of sediment formation on the surface disappears.

Work with hydrochloric acid can be carried out at any temperature inside the building (even at 10°C), and this does not cause noticeable changes in the composition of the solution.

Rice. 6.12. Equilibrium diagram liquid - vapor for the system HCl - H 2 O.

Rice. 6.13. Diagram of the state (fusibility) of the HCl–H 2 O system.

Rice. 6.14. Equilibrium in the HCl - FeCl 2 system.

Finally, another very important advantage of hydrochloric acid is full compatibility with a flux that uses chlorides.

Some disadvantage of hydrochloric acid as a reagent is its high volatility. The standards allow the concentration of 5 mg / m 3 of air volume in the workshop. The dependence of vapor pressure in the equilibrium state over acid of various percentage concentrations is given in table 6.10. In general, when the acid concentration in the bath is less than 15 wt %, this condition is satisfied. However, when temperatures rise in the workshop (that is, in summer time) it is possible to exceed this indicator. Certain information about what acid concentration at a particular shop temperature is acceptable can be determined from rice. 6.15.

The dependence of the etching rate on concentration and temperature is displayed in rice. 6.16.

Pickling deficiencies are usually caused by the following:

• using an acid with a greater or lesser concentration, compared to the optimal;
• short etching duration (the expected etching duration at different concentrations of acid and iron can be estimated from rice. 6.17;
• lower temperature compared to the optimum;
• lack of mixing;
• laminar motion of the pickling solution.

These problems are usually solved with the help of specific technological methods.

Table 6.10. Dependence of the equilibrium concentration of hydrogen chloride on the concentration of acid in the bath.

Acid concentration, %		Acid concentration, %	The concentration of HCl in the air, mg / m 3
	4500 (20°C)

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. AT 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. On the whole, 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 this: 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 laboratory conditions, you can use a long-standing method in which salt 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 in contact with skin or Airways 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. At healthy person normally, no more than 7 and at least 5 mmol of the substance per hour should be produced.

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 to 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 the synthetic detergents, rinse concentrate oral cavity caring for 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. preparations 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. At uncontrolled intake substances inside large quantities ulcers and erosion occur in digestive tract. You should seek help from a doctor.

Interaction

The substance is often used in combination with pepsin and other medicines. drugs. 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. AT medical purposes 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 .