It is he who helps digest food. Normally, stomach acid 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, would not stay in the stomach for 7 days.
What other experiments were carried out by scientists and how they added to the list of properties of hydrochloric acid, we will describe further.
Properties of hydrochloric acid
Hydrochloric acid formula It is a mixture of water and hydrogen chloride. Accordingly, the liquid is caustic, which allows it to destroy most substances.
The reagent is colorless. It gives off its scent. It is sour, suffocating. The aroma is sharp and, rather, is characterized as a stink.
If hydrochloric acid solution technical, it contains impurities of the 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 escape.
In this case, of course, the solution smokes. The maximum concentration is indicated for 20-degree air temperature. The higher the degrees, the faster the evaporation.
The density of 38% acid is just over 1 gram per cubic centimeter.
That is, even a concentrated substance is very watery. If you take a sip of this liquid, you will get burns.
But a weak 0.4% solution can be drunk. Naturally, in small quantities. Diluted acid has almost no smell, and it tastes tart and sour.
Hydrochloric acid interaction with other substances, largely justified by the monobasic composition of the reagent.
This means that only one hydrogen atom is included in the acid formula. This means that the reagent dissociates in water, that is, it dissolves completely.
The remaining substances, as a rule, dissolve already in the acid itself. So, in it all the metals that stand in front of hydrogen in the periodic system decay.
Dissolving in acid, they bind with chlorine. As a result, chlorides are obtained, that is,.
Reaction with hydrochloric acid will take place in most oxides and hydroxides of metals, as well as in them.
The main thing is that the latter are obtained from weaker acids. Salt is considered one of the strongest, put on a par with chamois.
From gases hydrochloric acid reacts violently with ammonia. This produces ammonium chloride. It crystallizes.
The particles are so small, and the reaction is so active, that the chloride rushes up. Outwardly it is smoke.
The reaction product with nitrate is also white. This interaction refers to the qualitatively determining hydrochloric.
The result of the reaction is a curdled precipitate. This is chloride. Unlike ammonium chloride, it rushes down, not up.
The reaction with nitrate is considered qualitative, since it is specific, not characteristic of other one-component acids.
They ignore the noble metals, of which the Argentum belongs. As you remember, it stands in the chemical series after hydrogen and, in theory, should not interact with hydrogen chloride dissolved in water.
Production of hydrochloric acid
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, sylvin, halite. All of these are minerals.
Under the word "halite" is hidden ordinary salt, which is eaten, that is, sodium chloride.
Sylvin is chloride, its shape is reminiscent of dice. Bischofite - chloride, is present in abundance on the lands of the Volga region.
All of the listed minerals are suitable for industrial production of the reagent.
However, the most commonly used chloride sodium. Hydrochloric acid obtained when table salt is treated with concentrated sulfuric acid.
The essence of the method is reduced to the dissolution of gaseous hydrogen chloride in water. Two more approaches are based on this.
The first is synthetic. Hydrogen is burned in chlorine. The second is off-gas, that is, passing.
Hydrogen chloride is used, which is simultaneously obtained when working with organic compounds, that is, hydrocarbons.
Off-gas 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.
Associated raw materials for hydrochloric acid can also be used when working with inorganic substances, for example, metal chlorides.
The same sylvin, for example, goes to the production of potash fertilizers. Plants also need magnesium.
Therefore, bischofite does not remain idle. As a result, they produce not only top dressing, but also hydrochloric acid.
The off-gas method displaces other methods for producing hydrochloric acid. The "side" industry accounts for 90% of the produced reagent. We will find out why it is made, where it is used.
The use of hydrochloric acid
Hydrochloric acid is used by metallurgists. The reagent is needed for decapitation of metals.
This is the name of the process of removing scale, rust, oxides and just dirt. Accordingly, private craftsmen also use acid, working, for example, with vintage items that have metal parts.
The reagent will dissolve their surface. There will be no trace of the problematic layer. But back to metallurgy.
In this industry, acid is beginning to be used to extract rare metals from ores.
The old methods are based on the use of their oxides. But, not all of them are easy to handle.
Therefore, the oxides began to be converted into chlorides, and then restored. Now, this is how they get, for example, and.
Since hydrochloric acid is contained in gastric juice, and a solution of low concentration can be drunk, it means that the reagent can also be used in the food industry.
Did you see the E507 additive on the product packaging? Know it's hydrochloric acid. It gives the very sourness and astringency to some cakes, sausages.
But, most often, a food emulsifier is 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 for patients with low stomach acidity.
It is no less dangerous than elevated. In particular, the likelihood of stomach cancer increases.
The body does not receive useful elements, even if a person takes vitamins and eats properly.
The fact is that for adequate, full-fledged absorption of useful substances, 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 for purification of drinking water, bleaching of fabrics, disinfection, production of plastic compounds, etc.
It turns out, being active and aggressive, hydrochloric acid is necessary for mankind. There is a demand, there is a 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 20-40 rubles.
The cost depends on the concentration. For a liter of purified reagent they give about 20 rubles more.
The price tag also depends on the container, packaging, form of sale. Acquisition of 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 give 100-160 rubles. This is the most expensive hydrochloric acid.
Buy a solution of hydrogen chloride in a liter container is also not cheap. The packaging is designed for a private consumer, therefore, they ask for about 400-500 rubles per bottle.
Technical acid in retail is less common, it costs about 100 rubles cheaper. The main one is wholesale.
Buying big companies. It is for them that the prices indicated at the beginning of the chapter are relevant. The giants do not sell at retail.
Accordingly, the cost of a substance in small shops is a reflection of the “appetites” of shop owners.
By the way, about appetite. If the acidity in the stomach is increased, food is digested faster, you want to eat more often.
This leads to thinness, gastritis and ulcers. People with low acidity are prone to slagging, because food “roams” in the stomach for a long time, is poorly absorbed.
This is reflected on the skin, usually in the form of acne and dots. Is there such a problem?
Think not about expensive cosmetics, but about checking the gastrointestinal tract.
Hydrochloric acid is a homogeneous colorless liquid with a pungent odor. It is a very caustic substance that interacts with most metals. Due to these properties, the material is widely used not only in industry, but also in everyday life.
The reagent is part of various means for getting rid of sewer blockages, but it can be used for this purpose on its own, after diluting it with water in the right proportions.
The use of an acid solution in the house is not limited to this: the material is used to clean plumbing fixtures from rust and limescale, remove stubborn stains from fabrics, and even to remove scale in a kettle.
Precautionary measures
Since the reagent is highly corrosive and releases toxic fumes when exposed to air, it is very important to use protective equipment when working with it.
When it comes into contact with the skin and mucous membranes, the material causes chemical burns, and with prolonged exposure to an HCl atmosphere, tooth decay, development of respiratory catarrh and ulceration of the nasal mucosa occur.
For protection purposes, you must use a gas mask, a rubberized apron, goggles and rubber gloves. Work should only be carried out in well-ventilated areas. If the reagent comes into contact with the skin or mucous membranes, rinse the affected area with plenty of running water and seek medical help.
How to get rid of blockages?
Diluted hydrochloric acid should be used for tough and targeted cleaning of sewers from organic deposits (fats, food residues, hair, detergents, etc.). This method is not suitable for steel, iron and plastic pipes, as the connection can lead to corrosion and even the formation of through holes.
Before starting the procedure, you need to close the drain holes in other plumbing and ensure the flow of air into the room. This step is necessary because during operation, the acid will begin to actively produce toxic gases.
It is recommended to dilute the composition with water until a concentration of 3-10% is reached, then pour directly into the sewer and leave for 1-2 hours. Then you need to rinse the pipes with plenty of water and, if necessary, repeat the procedure.
Important point! Do not mix with other drain cleaners, especially those based on alkalis. Otherwise, the reaction of these compounds will cause severe damage to the pipes.
Another use of acid in everyday life
With an acidic composition, you can easily clean limescale and rust from faience plumbing, remove urinary stone and other contaminants. For a greater effect, an inhibitor (for example, urotropin) is added to the agent, which slows down the chemical reaction.
The procedure is carried out as follows: the acid is diluted with water until a 5% concentration is reached and an inhibitor is added at the rate of 0.5 g per 1 liter of liquid. The surface is treated with the resulting composition and left for 30-40 minutes (depending on the degree of contamination), after which it is washed with water.
A mild acid solution is also used to remove berry stains, ink or rust stains from fabrics. To do this, the material is soaked in the composition for a while, after which it is thoroughly rinsed and washed in the usual way.
Getting rid of scale in the kettle
For this purpose, a 3-5% hydrochloric acid solution is used, which is poured into a kettle and heated to 60-80 ° C for 1-2 hours or until scale deposits disintegrate. After that, the scale becomes loose and is easily removed with a wooden spatula.
The effectiveness of the method is due to the fact that the reagent reacts with magnesium and calcium carbonates and converts them into soluble salts. The carbon dioxide released at the same time destroys the scale layer and makes it loose. After removing salt deposits, the dishes are thoroughly washed with clean water.
Important point! This method is not suitable for descaling chipped and cracked enamel or aluminum kettles: this will corrode the metal and severely damage it.
Conclusion
If you follow the precautions and safety rules, hydrochloric acid will become an indispensable assistant in everyday life. And you can buy it at the most affordable prices in our company.
In water it is called hydrochloric acid ( HCl).
Physical properties of hydrochloric acid
Under normal conditions, hydrochloric acid is a clear, colorless liquid with a sharp, unpleasant odor.
Concentrated hydrochloric acid contains 37% hydrogen chloride. Such an acid "smokes" in air. Hydrogen chloride is released from it, which, with water vapor in the air, forms a "fog" consisting of small droplets of hydrochloric acid. Hydrochloric acid is slightly heavier than water (the specific gravity of 37% hydrochloric acid is 1.19).
School laboratories use mostly dilute hydrochloric acid.
Chemical properties of hydrochloric acid
Hydrochloric acid solution has a sour taste. Litmus in this solution is red, while phenolphthalein remains colorless.
Substances whose color changes from the action of alkalis and acids are called indicators.
Litmus, phenolphthalein - indicators for acids and alkalis. With the help of indicators, you can determine whether there is acid or alkali in the solution.
Hydrochloric acid reacts with many metals. The interaction of hydrochloric acid with sodium is especially violent. This can be easily seen from the experiment that can be carried out in the device.
Concentrated hydrochloric acid is poured into a test tube up to about 1/4 of its volume, fixed in a tripod and a small piece of sodium (the size of a pea) is lowered into it. Hydrogen is released from the test tube, which can be set on fire, and small crystals of common salt settle to the bottom of the test tube.
From this experience it follows that sodium displaces hydrogen from the acid and combines with the rest of its molecule:
2Na + 2HCl \u003d 2NaCl + H 2?
Under the action of hydrochloric acid on zinc, hydrogen is released, and the substance zinc chloride ZnCl 2 remains in the solution.
Since zinc is divalent, each zinc atom replaces two hydrogen atoms in two hydrochloric acid molecules:
Zn + 2HCl \u003d ZnCl 2 + H 2?
Hydrochloric acid also acts on iron, aluminum and many other metals.
As a result of these reactions, hydrogen is released, and metal chlorides remain in the solutions: ferric chloride FeCl 2, aluminum chloride AlCl 3, etc.
These metal chlorides are the products of substitution of hydrogen in hydrochloric acid by metals.
Compound substances that can be considered as products of substitution of hydrogen in an acid by a metal are called salts.
Metal chlorides are salts of hydrochloric acid.
Neutralization reaction (equation)
A very important chemical property of hydrochloric acid is its interaction with bases. Consider first its interaction with alkalis, for example with caustic soda.
To this end, pour a small amount of dilute sodium hydroxide solution into a glass cup and add a few drops of litmus solution to it.
The liquid will turn blue. Then we will pour in small portions into the same glass a solution of hydrochloric acid from a graduated tube (burette) until the color of the liquid in the glass changes to violet. Violet litmus indicates that the solution contains neither acid nor alkali.
Such a solution is called neutral. After boiling water out of it, table salt NaCl will remain. Based on this experience, it can be concluded that when solutions of caustic soda and hydrochloric acid are drained, water and sodium chloride are obtained. Water molecules were formed from the combination of hydrogen atoms (from acid molecules) with hydroxyl groups (from alkali molecules). Molecules of sodium chloride were formed from sodium atoms (from alkali molecules) and chlorine atoms - acid residues. The equation for this reaction can be written as follows:
Na |OH + H| Cl \u003d NaCl + H 2 O
Other alkalis also react with hydrochloric acid - caustic potash, caustic calcium.
Let's get acquainted with how hydrochloric acid reacts with insoluble bases, for example, with copper oxide hydrate. To this end, we will place a certain amount of this base in a glass and carefully add hydrochloric acid to it until the copper oxide hydrate is completely dissolved.
After evaporation of the blue solution thus obtained, crystals of copper chloride CuCl 2 are obtained. Based on this, the following equation can be written:
And in this case, a reaction similar to the interaction of this acid with alkalis took place: hydrogen atoms from acid molecules combined with hydroxyl groups from base molecules, water molecules were formed. Copper atoms combined with chlorine atoms (residues from acid molecules) and formed salt molecules - copper chloride.
Hydrochloric acid reacts in the same way with other insoluble bases, for example, with iron oxide hydrate:
Fe(OH) 3 + 3HCl = 3H 2 O + FeCl 3
The reaction of an acid with a base to form a salt and water is called neutralization.
Hydrochloric acid is found in small amounts in the gastric juice of humans and animals and plays an important role in digestion.
Hydrochloric acid is used to neutralize alkalis, to obtain chloride salts. It also finds application in the production of some plastics, medicines.
The use of hydrochloric acid
Hydrochloric acid has a wide range of uses in the national economy, and you will often meet it when studying chemistry.
Large amounts of hydrochloric acid are used to pickle steel. Nickel-plated, zinc-plated, tin-plated (tin-plated), chrome-plated products are widely used in everyday life. To cover steel products and sheet iron with a layer of protective metal, the iron oxide film must first be removed from the surface, otherwise the metal will not stick to it. Removal of oxides is achieved by etching the product with hydrochloric or sulfuric acid. The disadvantage of etching is that the acid reacts not only with the oxide, but also with the metal. To avoid this, a small amount of an inhibitor is added to the acid. Inhibitors are substances that slow down an unwanted reaction. Inhibited hydrochloric acid can be stored in steel containers and transported in steel tanks.
A solution of hydrochloric acid can also be bought at a pharmacy. Doctors prescribe a dilute solution of her patients with low acidity of gastric juice.
Hydrochloric acid is a clear, colorless or yellowish liquid without suspended or emulsified particles.
Hydrochloric acid is a solution of gaseous hydrogen chloride HCl in water. The latter is a hygroscopic colorless gas with a pungent odor. The commonly used concentrated hydrochloric acid contains 36-38% hydrogen chloride and has a density of 1.19 g/cm3. Such an acid smokes in air, as gaseous HCl is released from it; when combined with air moisture, tiny droplets of hydrochloric acid are formed. It is a strong acid and reacts vigorously with most metals. However, metals such as gold, platinum, silver, tungsten and lead are practically not etched with hydrochloric acid. Many base metals dissolve in acid to form chlorides, such as zinc:
Zn + 2HCl \u003d ZnCl 2 + H 2
Pure acid is colorless, while technical acid has a yellowish tint caused by traces of compounds of iron, chlorine and other elements (FeCl3). Often a dilute acid containing 10% or less hydrogen chloride is used. Diluted solutions do not emit gaseous HCl and do not smoke in either dry or humid air.
The use of hydrochloric acid
Hydrochloric acid is widely used in industry for extracting metals from ores, pickling metals, etc. It is also used in the manufacture of soldering fluid, in the deposition of silver, and as an integral part of aqua regia.
The scale of the use of hydrochloric acid in industry is less than that of nitric acid. This is due to the fact that hydrochloric acid causes corrosion of steel equipment. In addition, its volatile vapors are quite harmful and also cause corrosion of metal products. This must be taken into account when storing hydrochloric acid. Hydrochloric acid is stored and transported in rubber-lined tanks and barrels, i.e. in vessels, the inner surface of which is covered with acid-resistant rubber, as well as in glass bottles and polyethylene utensils.
Hydrochloric acid is used to produce chlorides of zinc, manganese, iron and other metals, as well as ammonium chloride. Hydrochloric acid is used to clean the surfaces of metals, vessels, wells from carbonates, oxides and other sediments and contaminants. In this case, special additives are used - inhibitors that protect the metal from dissolution and corrosion, but do not delay the dissolution of oxides, carbonates and other similar compounds.
HCl is used in the industrial production of synthetic resins, rubbers. It is used as a raw material in the production of methyl chloride from methyl alcohol, ethyl chloride from ethylene, and vinyl chloride from acetylene.
Hydrochloric acid poisoning
HCl is poisonous. Poisoning usually occurs by mist formed when the gas interacts with water vapor in the air. HCl is also absorbed on the mucous membranes with the formation of acid, which causes severe irritation. With prolonged work in an HCl atmosphere, catarrhs of the respiratory tract, tooth decay, ulceration of the nasal mucosa, and gastrointestinal disorders are observed. Permissible content of HCl in the air of working premises is not more than 0.005 mg/l. For protection use a gas mask, goggles, rubber gloves, shoes, apron.
At the same time, our digestion is impossible without hydrochloric acid, its concentration in gastric juice is quite high. If the acidity in the body is lowered, then digestion is disturbed, and doctors prescribe such patients to take hydrochloric acid before eating.
The use of hydrochloric acid in everyday life
Concentrated "hodgepodge" is mixed with water in any proportion for domestic needs. A strong solution of this inorganic acid easily cleans earthenware plumbing from limescale and rust, while a weaker solution can remove rust stains, ink, and berry juice from fabrics.
If you look closely, the toilet duck cleaner says that it contains hydrochloric acid, so you need to work with it in rubber gloves and protect your eyes from splashing into them.
In addition, the life of no person is unthinkable without this acid - it is contained in the stomach and it is thanks to it that the food that has entered the stomach is dissolved (digested).
In addition, this acid serves as the first barrier against pathogenic bacteria that enter the stomach - they die in an acidic environment.
Well, people suffering from gastritis with high acidity, this acid is also well known. They even reduce its effect so that it does not destroy the walls of the stomach, with the help of special drugs that interact with it and reduce its concentration.
The most popular are preparations containing magnesium and aluminum oxides, for example, Maalox. However, there are extreme people who drink baking soda, although it has already been proven that this only leads to temporary relief.
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 off-gas hydrochloric acid in the volume of production 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 when high purity is required. 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.
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 mist 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.
