Protective equipment. Hydrochloric acid - physical properties

Instructions

Take a test tube that supposedly contains hydrochloric acid (HCl). Add a little to this container solution silver nitrate (AgNO3). Proceed with caution and avoid contact with skin. Silver nitrate can leave black marks on the skin, which can only be removed after a few days, and salt exposure on the skin acids may cause severe burns.

Watch what happens to the resulting solution. If the color and consistency of the contents of the test tube remain unchanged, this will mean that the substances have not reacted. In this case, it will be possible to conclude with confidence that the substance being tested was not .

If a white precipitate appears in the test tube, the consistency of which resembles cottage cheese or curdled milk, this will indicate that the substances have reacted. The visible result of this reaction was the formation of silver chloride (AgCl). It is the presence of this white cheesy sediment that will be direct evidence that initially there was indeed hydrochloric acid in your test tube, and not any other acid.

Pour some of the test liquid into a separate container and drop in a little lapis solution. In this case, a “curdy” white precipitate of insoluble silver chloride will instantly form. That is, there is definitely a chloride ion in the molecule of the substance. But maybe it’s not, after all, but a solution of some kind of chlorine-containing salt? For example, sodium chloride?

Remember another property of acids. Strong acids (and hydrochloric acid, of course, is one of them) can displace weak acids from them. Place a little soda powder - Na2CO3 - in a flask or beaker and slowly add the liquid to be tested. If there is a hissing sound immediately and the powder literally “boils”, there will be no doubt left - it is hydrochloric acid.

Why? Because this reaction is: 2HCl + Na2CO3 = 2NaCl + H2CO3. Carbonic acid is formed, which is so weak that it instantly decomposes into water and carbon dioxide. It was his bubbles that caused this “boiling and hissing.”

Hydrochloric acid (hydrochloric acid, an aqueous solution of hydrogen chloride), known as HCl, is a caustic chemical compound. Since ancient times, people have been using this colorless liquid for various purposes, which emits a light smoke in the open air.

Properties of a chemical compound

HCl is used in various areas of human activity. It dissolves metals and their oxides, is absorbed in benzene, ether and water, and does not destroy fluoroplastic, glass, ceramics and graphite. Its safe use is possible when stored and operated in the correct conditions, in compliance with all safety standards.

Chemically pure (CP) hydrochloric acid is formed during gaseous synthesis from chlorine and hydrogen, giving hydrogen chloride. It is absorbed in water, resulting in a solution containing 38-39% HCl at +18 C. An aqueous solution of hydrogen chloride is used in various areas of human activity. The price of chemically pure hydrochloric acid is variable and depends on many components.

Areas of application of aqueous hydrogen chloride solution

The use of hydrochloric acid has become widespread due to its chemical and physical properties:

• in metallurgy, in the production of manganese, iron and zinc, technological processes, metal purification;
• in galvanoplasty - during etching and pickling;
• in the production of soda water to regulate acidity, in the production of alcoholic beverages and syrups in the food industry;
• for leather processing in light industry;
• when purifying non-drinking water;
• for optimization of oil wells in the oil industry;
• in radio engineering and electronics.

Hydrochloric acid (HCl) in medicine

The most famous property of hydrochloric acid solution is the equalization of the acid-base balance in the human body. Low stomach acidity is treated with a weak solution or drugs. This optimizes the digestion of food and helps fight germs and bacteria that penetrate from the outside. HCl hydrochloric acid helps normalize low levels of gastric acidity and optimizes protein digestion.

Oncology uses HCl to treat tumors and slow down their progression. Hydrochloric acid preparations are prescribed for the prevention of stomach cancer, rheumatoid arthritis, diabetes, asthma, urticaria, cholelithiasis and others. In folk medicine, hemorrhoids are treated with a weak acid solution.

You can find out more about the properties and types of hydrochloric acid.

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 “smoke” in air, since the released gaseous HCl forms tiny droplets of hydrochloric acid with water vapor.

Hydrochloric acid is not flammable or explosive. It is one of the strongest acids; it dissolves (with the release of hydrogen and the formation of salts - chlorides) all metals in the voltage series up to hydrogen. Chlorides are also formed when hydrochloric acid reacts with metal oxides and hydroxides. It behaves as a reducing agent with strong oxidizing agents.

Salts of hydrochloric acid - chlorides, with the exception of AgCl, Hg2Cl2, are highly soluble in water. Glass, ceramics, porcelain, graphite, and fluoroplastic 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.

The produced technical hydrochloric acid has a strength of at least 31% HCl (synthetic) and 27.5% HCl (from NaCl). A 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 produce chlorides of various metals, organic intermediates and synthetic dyes, acetic acid, activated carbon, various adhesives, hydrolytic alcohol, and in electroplating. 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, and in the leather industry, leather is treated with acid before tanning and dyeing. Hydrochloric acid is used in the textile, food industries, medicine, etc.

Hydrochloric acid plays an important role in the digestive process; 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 rubberized (rubber-coated) metal vessels, as well as in plastic containers.

Hydrochloric acid very dangerous to human health. Causes severe burns upon contact with skin. Contact with eyes is especially dangerous.

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

Fog and hydrogen chloride vapors formed when concentrated acid interacts with air are very dangerous. They irritate the mucous membranes and respiratory tract. Prolonged work in an HCl atmosphere 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, and cough.

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

Secondly, it can leak into groundwater, which can result in contamination of inland waters.
Where the water in rivers and lakes has become quite acidic (pH less than 5), fish disappear. When trophic chains are disrupted, the number of species of aquatic animals, algae and bacteria decreases.

In cities, acid precipitation accelerates the destruction of marble and concrete structures, monuments and sculptures. When it comes into contact with metals, hydrochloric acid causes corrosion, and when it reacts with substances such as bleach, manganese dioxide, or potassium permanganate, it forms toxic chlorine gas.

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

The material was prepared based on information from open sources

It is what helps digest food. Normally, acid in the stomach is 0.3%.

This is enough to destroy a razor blade. It only takes about a week. The experiments, of course, were carried out outside the human body.

A dangerous object would damage the esophagus and would not stay in the stomach for 7 days.

We will tell you further what other experiments the scientists performed and how they added to the list of properties of hydrochloric acid.

Properties of hydrochloric acid

Hydrochloric acid formula is a mixture of water and hydrogen chloride. Accordingly, the liquid is caustic, which allows it to destroy most substances.

The reagent is colorless in appearance. Its smell gives it away. It is sour, suffocating. The aroma is pungent and, rather, is characterized as a stench.

If hydrochloric acid solution technical, it contains impurities of diatomic and. They give the liquid a yellowish tint.

Unlike, for example, mass of hydrochloric acid in solution cannot exceed 38%.

This is the critical point at which the substance simply evaporates. Both hydrogen chloride and water evaporate.

Naturally, the solution smokes. The maximum concentration is indicated for 20-degree air temperature. The higher the degrees, the faster the evaporation occurs.

The density of 38 percent acid is slightly more than 1 gram per cubic centimeter.

That is, even a concentrated substance is very watery. If you drink this liquid, you will get burns.

But you can drink a weak 0.4 percent solution. Naturally, in small quantities. Dilute acid has almost no smell, and its taste is tart and sour.

Reaction of hydrochloric acid with other substances, is largely justified by the monobasic composition of the reagent.

This means that the acid formula contains only one hydrogen atom. This means that the reagent dissociates in water, that is, it dissolves completely.

The remaining substances, as a rule, dissolve in the acid itself. Thus, all metals that stand in front of hydrogen in the periodic table disintegrate in it.

When dissolved in acid, they bind with chlorine. As a result, chlorides are obtained, that is, .

Reaction with hydrochloric acid occurs in most metal oxides and hydroxides, as well as in their .

The main thing is that the latter are obtained from weaker acids. Salt is considered one of the strongest, ranking with chamois.

From gases hydrochloric acid Reacts violently with ammonia. In this case, ammonium chloride is formed. It crystallizes.

The particles are so small and the reaction is so active that the chloride rushes upward. Outwardly it is smoke.

The reaction product with nitrate is also white. This interaction is one of the qualitatively determining salt interactions.

The result of the reaction is a cheesy sediment. This is chloride. Unlike ammonium chloride, it rushes down, not up.

The reaction with nitrate is considered qualitative because it is specific, not characteristic of other one-component acids.

They ignore noble metals, which include argentum. As you remember, it is in the chemical series after hydrogen and, in theory, should not interact with hydrogen chloride dissolved in water.

Hydrochloric acid production

Hydrochloric acid is released not only in laboratory conditions, but also in nature. The human body is part of it.

But, hydrochloric acid in the stomach has already been discussed. However, this is not the only natural source, and in the literal sense.

The reagent is found in some geysers and other water outlets of volcanic origin.

As for hydrogen chloride separately, it is part of bischofite, sylvite, and halite. All these are minerals.

The word “halite” means ordinary salt that is used in food, that is, sodium chloride.

Silvin is a chloride and is shaped like dice. Bishofite is a chloride, present in abundance in the Volga region.

All of the listed minerals are suitable for industrial production of the reagent.

But, most often they use chloride sodium Hydrochloric acid is obtained when table salt is exposed to concentrated sulfuric acid.

The essence of the method is to dissolve hydrogen chloride gas in water. Two other approaches are based on this.

The first one is synthetic. Hydrogen is burned in chlorine. The second is off-gas, that is, associated.

Hydrogen chloride is used, which is incidentally obtained when working with organic compounds, that is, hydrocarbons.

Absent hydrogen chloride is formed during dehydrochlorination and chlorination of organic matter.

The substance is also synthesized during the pyrolysis of organochlorine waste. Chemists call pyrolysis the decomposition of hydrocarbons under conditions of oxygen deficiency.

Hydrochloric acid can also be used as a by-product when working with inorganic substances, for example, metal chlorides.

The same sylvite, for example, is used to produce potassium fertilizers. Plants also need magnesium.

Therefore, bischofite does not remain idle. As a result, they produce not only fertilizing, but also hydrochloric acid.

The gas-absorbing method displaces other methods of producing hydrochloric acid. The “by-product” industry accounts for 90% of the reagent produced. Let's find out why it is made and where it is used.

Application of hydrochloric acid

Hydrochloric acid is used by metallurgists. The reagent is needed for pickling metals.

This is the name for the process of removing scale, rust, oxides and just dirt. Accordingly, private craftsmen also use acid when working, for example, with vintage items that contain metal parts.

The reagent will dissolve their surface. There will be no trace left of the problem layer. But, let's return to metallurgy.

In this industry, acid is beginning to be used to extract rare metals from ores.

Old methods are based on the use of their oxides. But, not all of them are easy to process.

Therefore, the oxides began to be converted into chlorides, and then reduced. Now, this is how they get, for example, and.

Since hydrochloric acid is contained in gastric juice, and a low concentration solution can be drunk, it means that the reagent can be used in the food industry.

Did you see the E507 additive on the product packaging? Know that this is hydrochloric acid. It gives that very sourness and tartness to some cakes and sausages.

But most often food emulsifiers are added to fructose, gelatin and citric acid.

E507 is needed not only for taste, but also as an acidity regulator, that is, the Ph of the product.

Hydrochloric acid can be used in medicine. A weak solution of hydrochloric acid is prescribed to patients with low stomach acidity.

It is no less dangerous than increased. In particular, the likelihood of stomach cancer increases.

The body does not receive enough useful elements, even if a person takes vitamins and eats right.

The fact is that for adequate, complete absorption of nutrients, standard acidity is needed.

The last use of the reagent is obvious. Chlorine is obtained from acid. It is enough to evaporate the solution.

Chlorine is used to purify drinking water, bleach fabrics, disinfect, produce plastic compounds, etc.

It turns out that hydrochloric acid, being active and aggressive, is necessary for humanity. There is demand, there is supply. Let's find out the price of the issue.

Hydrochloric acid price

Price product depends on the type. Technical acid is cheaper, purified acid is more expensive. For a liter of the first they ask for 20-40 rubles.

Cost depends on concentration. For a liter of purified reagent they cost about 20 rubles more.

The price tag also depends on the container, packaging, and form of sale. Purchasing acid in plastic canisters of 25-40 liters is more profitable.

In the medical field, in retail, the substance is offered in glass.

For 50 milliliters you will pay 100-160 rubles. This is the most expensive hydrochloric acid.

Buy Hydrogen chloride solution in a liter container is also not cheap. The packaging is designed for private consumers, so they ask for about 400-500 rubles per bottle.

Technical acid is less common in retail and costs about 100 rubles less. The main one is wholesale.

Large enterprises are being purchased. It is for them that the prices indicated at the beginning of the chapter are relevant. The giants do not sell retail.

Accordingly, the cost of the substance in small stores is a reflection of the “appetites” of the store owners.

By the way, about appetite. If the acidity in the stomach is increased, food is digested faster, and you want to eat more often.

This leads to thinness, gastritis and ulcers. People with low acidity are prone to slagging, because food “ferments” in the stomach for a long time and is poorly digested.

This is reflected on the skin, usually in the form of acne and spots. Is there such a problem?

Think not about expensive cosmetics, but about checking your gastrointestinal tract.

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

Table 6.2

The amount of commercial acid in volume units required to obtain 1 m3 of working solution of a given concentration is determined by the formula:

V Т = n(r З - 1000)/(r Т - 1000) (5.2)

where n is the number of cubic meters of solution;

V T - volume of commercial acid, m 3;

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

r Z is the specified 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 m3 of 12% HCl solution, if the density of the commercial acid is 1150 kg/m3. From Table 6.2 we find that the density of a 12% HCl solution is 1060 kg/m3. Then

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

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

r Z = (14 × 1150 + 21 × 1000)/35 = 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 pumping 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 wellhead fittings.

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

To protect pipes, tanks, pumps, pipelines, wellhead and well 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 acetic (0.8-1.6%) and hydrofluoric (1-2%) acids based on the volume of diluted hydrochloric acid.

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

In the fields, acid is pumped into the formation under pressure, acid baths are used to clean the face surface from contaminating deposits (cement, clay solution, resins, paraffin), as well as the 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 formations, special units Azinmash - 30A, AKPP - 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-action pump 5NK - 500 driven by a travel engine through a power take-off box, a manifold, rubberized main tanks (6-10 m 3) and on a trailer (6 m 3).