Tank with hydrochloric acid
One of the strong monobasic acids and is formed when gas dissolves hydrogen chloride(HCl) in water is a clear, colorless liquid with a characteristic odor of chlorine. Dilute hydrochloric acid(as well as phosphorus) is often used to remove oxides when soldering metals.
Sometimes the gaseous compound HCl is mistakenly called hydrochloric acid. HCl is a gas that when dissolved in water forms hydrochloric acid.
Hydrogen chloride- a colorless gas with a sharp suffocating odor of chlorine. It turns into a liquid state at -84 0 C, and at -112 0 C it turns into a solid state.
Hydrogen chloride very soluble in water. So at 0 0 C, 500 liters of hydrogen chloride dissolve in 1 liter of water.
In its dry state, hydrogen chloride gas is quite inert, but it can already interact with some organic substances, for example with acetylene (a gas that is released when carbide is lowered into water).
Chemical properties of hydrochloric acid
Chemical reaction with metals:
2HCl + Zn = ZnCl 2 + H 2 - salt is formed (in this case, a clear solution of zinc chloride) and hydrogen
- chemical reaction with metal oxides:
2HCl + CuO = CuCl 2 + H 2 O - salt is formed (in this case, a solution of green copper chloride salt) and water
- chemical reaction with bases and alkalis (or neutralization reaction)
HCl + NaOH = NaCl + H 2 O - neutralization reaction - salt is formed (in this case, a clear solution of sodium chloride) and water.
- chemical reaction with salts (for example, with chalk CaCO 3):
HCl + CaCO 3 = CaCl 2 + CO 2 + H 2 O - carbon dioxide, water and a clear solution of calcium chloride CaCl 2 are formed.
Obtaining hydrochloric acid
Hydrochloric acid are obtained using a chemical reaction of the compound:
H 2 + Cl 2 = HCl - the reaction occurs at elevated temperatures
And also in the interaction of table salt and concentrated sulfuric acid:
H 2 SO 4 (conc.) + NaCl = NaHSO 4 + HCl
In this reaction, if the substance NaCl is in solid form, then HCl is a gas hydrogen chloride, which when dissolved in water forms hydrochloric acid
There are complex chemical substances that are similar in chemical structure to hydrochloric acid, but contain from one to four oxygen atoms per molecule. These substances can be called oxygen-containing acids. With an increase in the number of oxygen atoms, the stability of the acid and its oxidizing ability increase.
TO oxygen-containing acids the following:
- hypochlorous (HClO),
- chloride (HClO 2),
- chloric acid (HClO 3),
- chlorine (HClO 4).
Each of these chemical complexes has all properties of acids and is capable of forming salts. Hypochlorous acid(HClO) forms hypochlorites, for example, the compound NaClO is sodium hypochlorite. Hypochlorous acid itself is formed when chlorine is dissolved in cold water by a chemical reaction:
H 2 O + Cl 2 = HCl + HClO,
As you can see, in this reaction two acids are formed at once - salt HCl and hypochlorous HClO. But the latter is an unstable chemical compound and gradually turns into hydrochloric acid;
Chloride HClO 2 forms chlorites, salt NaClO 2 - sodium chlorite;
hypochlorous(HClO3) - chlorates, compound KClO 3, - potassium chlorate (or Berthollet's salt) - by the way, this substance is widely used in the manufacture of matches.
And finally, the strongest known monobasic acid - chlorine(HClO 4) - colorless, fuming in air, highly hygroscopic liquid - forms perchlorates, for example, KClO 4 - potassium perchlorate.
Salts formed hypochlorous HClO and chloride HClO 2 acids are unstable in the free state and are strong oxidizing agents in aqueous solutions. But the salts formed hypochlorous HClO 3 and chlorine HClO 4 with acids based on alkali metals (for example, Berthollet salt KClO 3) are quite stable and do not exhibit oxidizing properties.
Hydrogen chloride is a colorless gas heavier than air with a pungent odor, which consists of equal volumes of chlorine and hydrogen, formula: HCl
A mixture of chlorine and hydrogen reacts violently and explodes even in sunlight, forming hydrogen chloride.
Hydrogen chloride itself is not a flammable gas.
In the laboratory, you can obtain hydrogen chloride using concentrated sulfuric acid + table salt and heating this mixture.
Hydrogen chloride gas dissolves well in water, the solution itself is called.
At high concentrations, hydrochloric acid seems to smoke in the air, as hydrogen chloride is gradually released from the solution into the external moisture of the air. When heated, the release of hydrogen chloride becomes more intense.
Hydrochloric acid is widely used to remove rust from surfaces. However, this can only be done with the use of inhibitors (additives that slow down the reaction of the metal with the acid) so that the acid does not spoil the metal itself. Salts are also obtained from acid, used in medicine, etc. This acid is even secreted by our stomach to digest food, but the concentration there is very low (0.2-0.5%).
Salts of this acid are called chlorides. Chlorides are also generally soluble in water.
If you add silver nitrate (AgNO 3) to hydrochloric acid or its salt, a white cheesy precipitate forms. This precipitate is insoluble in acids, which always makes it possible to establish the presence of chloride ions.
Lesson No. 9th grade date: _____
Lesson topic. Hydrogen chloride: preparation and properties.
Lesson type: combined lesson.
Objective of the lesson: consider methods of production and properties of hydrogen chloride; teach to correlate the areas of application of hydrogen chloride with its properties.
Lesson objectives:
Educational: introduce students to the chemical formula and structure of the hydrogen chloride molecule, physical and chemical properties, production and use of hydrogen chloride.
Methods and techniques:
Equipment: textbook “Chemistry 9th grade” Rudzitis G.E., Feldman F.G.; periodic table of chemical elements D.I. Mendeleev; cards with individual tasks, handouts.
PROGRESS OF THE LESSON
Organizational moment.
Checking homework.
Frontal conversation.
- Tell us about the physical properties of chlorine (chlorine is a gas, yellow-green in color, has a pungent, suffocating odor. Poisonous for all living organisms. 2.5 times heavier than air. Boils at a temperature of +15 ºС).
How does the chemical activity of halogens change from fluorine to iodine? (fluorine is chemically the most active, and iodine is the least active).
How does the displacement activity of halogens change in solutions of their salts? (more active halogens displace less active halogens from their compounds).
What simple substances does chlorine react with? (with metals and hydrogen).
Describe the interaction of chlorine with water, revealing the essence of the reaction (Cl 2 + H 2 O = HCl + HClO. An exchange reaction results in the formation of two acids: hydrochloric and hypochlorous; OVR).
- Tell us about possible cases of the reaction of chlorine with hydrogen, the mechanism and essence of the reaction (chlorine reacts with hydrogen in the light, as well as when heated; it explodes when irradiated, forming hydrogen chloride).
How does hydrogen chloride dissolve in water and what is its solution? (dissolves very well in water, hydrochloric acid is formed).
Written homework. (This is done on the board by students, while students are doing tasks at the board, the teacher conducts a frontal conversation with the class).
Individual task.
MnO 2 ) with muric acid."
This gas is chlorine. When chlorine interacts with hydrogen, hydrogen chloride is formed, an aqueous solution of “muric acid” - hydrochloric acid. When the mineral pyrolusite is heated with hydrochloric acid, chlorine is formed according to the reaction:
4HCl + MnO 2 = MnCl 2 +Cl 2 + 2H 2 O
Learning new material.
The chemical formula of hydrogen chloride isHCl. The chemical bond is polar covalent.
In industry, hydrogen chloride is produced by reacting chlorine with hydrogen.
Cl 2 + H 2 = 2 HCl
In the laboratory it is prepared by heating sodium chloride with concentrated sulfuric acid. Under such conditions, in the absence of water, hydrogen chloride gas is released, which is then dissolved in water to produce hydrochloric acid.
2NaCl + H 2 SO 4 = Na 2 SO 4 + 2HCl (cm. rice. 13 §14).
Hydrogen chloride is a colorless gas, slightly heavier than air, with a pungent odor, and smokes in moist air. The most characteristic property of hydrogen chloride is its high solubility in water (at 0 ºС, about 500 volumes of gas dissolve in one volume of water).
Is it possible to obtain hydrogen chloride using a solution of table salt? (no, because all substances in solution are strong electrolytes).
Chemical properties: Hydrogen chloride does not react with metals or basic oxides (unlike hydrochloric acid). Remember that hydrochloric acid and hydrogen chloride are not the same substance, although they are described by the same formula. These substances have different physical and chemical properties.
Solving problematic issues.
It has been established that river waters near volcanoes contain hydrochloric acid. Make an assumption about the origin of this phenomenon (hydrogen chloride is one of the components of poisonous volcanic gases).
Questions - tips: what is gastric juice? Remember the composition of gastric juice? What is the role of hydrochloric acid in digestion? For what digestive disorders is a highly diluted solution of hydrochloric acid prescribed?
Homework . Learn the material § 14, complete No. 1-2 p. 55.
Individual task.
Analyze the text, identify the substances and write down the equations for the reactions described:
“During the First World War (1915), poison gas was used for the first time near the city of Ypres in western Flanders. This gas attack claimed the lives of 5 thousand soldiers and disabled about 15 thousand. The interaction of this gas with hydrogen can occur explosively; an aqueous solution of the product of this reaction was previously called “muric acid.” One of the discoverers of poisonous gas was the Swedish chemist and pharmacist Karl Scheele, who obtained it by heating the mineral pyrolusite ( MnO 2 ) with muric acid."
Solving problematic issues.
It is known that hydrogen chloride and hydrochloric acid are toxic substances that have a toxic effect on the human body. At the same time, for some stomach diseases, doctors prescribe hydrochloric acid as a medicine.
Problematic question: “What explains the actions of a doctor who prescribes a toxic substance to a patient as a medicine?”
Solving problematic issues.
It has been established that river waters near volcanoes contain hydrochloric acid. Make a guess about the origin of this phenomenon.
It is known that hydrogen chloride and hydrochloric acid are toxic substances that have a toxic effect on the human body. At the same time, for some stomach diseases, doctors prescribe hydrochloric acid as a medicine.
Problematic question: “What explains the actions of a doctor who prescribes a toxic substance to a patient as a medicine?”
Solving problematic issues.
It has been established that river waters near volcanoes contain hydrochloric acid. Make a guess about the origin of this phenomenon.
It is known that hydrogen chloride and hydrochloric acid are toxic substances that have a toxic effect on the human body. At the same time, for some stomach diseases, doctors prescribe hydrochloric acid as a medicine.
Problematic question: “What explains the actions of a doctor who prescribes a toxic substance to a patient as a medicine?”
Solving problematic issues.
It has been established that river waters near volcanoes contain hydrochloric acid. Make a guess about the origin of this phenomenon.
It is known that hydrogen chloride and hydrochloric acid are toxic substances that have a toxic effect on the human body. At the same time, for some stomach diseases, doctors prescribe hydrochloric acid as a medicine.
Problematic question: “What explains the actions of a doctor who prescribes a toxic substance to a patient as a medicine?”
Lesson No. 9th grade date: _____
Lesson topic. Hydrochloric acid and its salts.
Lesson type: combined lesson.
Objective of the lesson: generalize knowledge about the properties of hydrochloric acid, introduce qualitative reactions to halide ions.
Lesson objectives:
Educational: consider the empirical formula of hydrochloric acid and chlorides, study the meaning of qualitative reactions, conduct a chemical experiment to recognize the most important inorganic substances, recognize chlorides, draw up equations of reactions characteristic of hydrochloric acid.
Educational: show the unity of the material world.
Developmental: acquiring independent work skills.
Methods and techniques: frontal conversation, individual, independent work.
Equipment: textbook “Chemistry 9th grade” Rudzitis G.E., Feldman F.G.; periodic table of chemical elements D.I. Mendeleev; cards with individual tasks, handouts, a set of reagents: hydrochloric acid solution, zinc, silver nitrate.
PROGRESS OF THE LESSON
Organizational moment.
Preparation for the perception of new material.
Safety instructions when working with acids.
Questions on the topic studied.
Prove that hydrochloric acid contains hydrogen (reaction of hydrochloric acid with zinc; observation of gas).
Zn + 2 HCl = ZnCl 2 + H 2
Prove that hydrochloric acid contains chlorine (carrying out a qualitative reaction on hydrochloric acid and its salts - a reaction with silver nitrateAgNO 3 ; observation of the precipitation of a white precipitate of silver chloride).
AgNO 3 + HCl = AgCl↓ + HNO 3
How to carry out the transformation reflected in the diagram:
CuO → CuCl 2 → AgCl
CuO + 2HCl = CuCl 2 +H 2 O
CuCl 2 + 2AgNO 3 = 2AgCl↓ + Cu(NO 3 ) 2
Learning new material.
Conducting a research assignment.
Describe the physical properties of hydrochloric acid using your observations and textbook data, p. 56 (colorless liquid with a pungent odor).
Read the textbook article p. 56 about methods for producing hydrochloric acid in the laboratory and industry.
2. Study of the chemical properties of hydrochloric acid.
Drawing up a diagram reflecting the chemical properties of hydrochloric acid, common with other acids, and specific properties.
Completing task No. 2 p.58.
Salts of hydrochloric acid.
NaCl– table salt – is a constant companion of a person throughout his life, as eloquently evidenced by the history of mankind.
What is the meaning of the famous proverb “Having eaten unsalted”?
What, in your opinion, are the prerequisites for the emergence of the ancient cities of Russia - Solikamsk, Soligorsk, Solvychegorsk, etc.?
Posing a problematic question: “What explains this attitude of people towards an ordinary substance known to all of us? Why is table salt always and everywhere considered an essential product?” (Table salt as a food additive is the most important source of the formation of hydrochloric acid in the body, which is a necessary component of gastric juice. The intake of sodium chloride into the body maintains the constancy of the chemical composition of the blood).
Consolidation of the studied material.
Doing independent work.
Write down equations for feasible reactions:
1 option
NaOH + HCl →
NaCl + AgNO 3 →
NaCl + KNO 3 →
Na 2 CO 3 + HCl →
Option 2
Ca( OH) 2 + HCl →
KCl + AgNO 3 →
HCl + AgNO 3 →
K 2 CO 3 + HCl →
Option 3
Ba( OH) 2 + HCl →
BaCl 2 + AgNO 3 →
KCl + AgNO 3 →
BaCO 3 + HCl →
Homework . Learn the material § 15, complete No. 3, 5 p. 58. Individual task * No. 4 p. 58.
1 option
NaOH + HCl →
NaCl + AgNO 3 →
NaCl + KNO 3 →
Na 2 CO 3 + HCl →
Option 2
Ca( OH) 2 + HCl →
KCl + AgNO 3 →
HCl + AgNO 3 →
K 2 CO 3 + HCl →
3 option
Ba(OH) 2 + HCl →
BaCl 2 + AgNO 3 →
KCl + AgNO 3 →
BaCO 3 + HCl →
hydrochloric acid, hydrogen chloride formula
Hydrogen chloride, hydrogen chloride(HCl) is a colorless, thermally stable gas (under normal conditions) with a pungent odor, fumes in moist air, easily dissolves in water (up to 500 volumes of gas per volume of water) to form hydrochloric (hydrochloric) acid. At −85.1 °C it condenses into a colorless, mobile liquid. At −114.22 °C, HCl turns into a solid state. In the solid state, hydrogen chloride exists in the form of two crystalline modifications: orthorhombic, stable below −174.75 °C, and cubic.
- 1 Properties
- 2 Receipt
- 3 Application
- 4 Security
- 5 Notes
- 6 Literature
- 7 Links
Properties
An aqueous solution of hydrogen chloride is called hydrochloric acid. When dissolved in water, the following processes occur:
The dissolution process is highly exothermic. With water, HCl forms an azeotropic mixture containing 20.24% HCl.
Hydrochloric acid is a strong monobasic acid; it energetically interacts with all metals in the voltage series to the left of hydrogen, with basic and amphoteric oxides, bases and salts, forming salts - chlorides:
Chlorides are extremely common in nature and have the widest application (halite, sylvite). Most of them are highly soluble in water and completely dissociate into ions. Slightly soluble are lead chloride (PbCl2), silver chloride (AgCl), mercury(I) chloride (Hg2Cl2, calomel) and copper(I) chloride (CuCl).
When exposed to strong oxidizing agents or during electrolysis, hydrogen chloride exhibits reducing properties:
When heated, hydrogen chloride is oxidized by oxygen (catalyst - copper(II) chloride CuCl2):
Concentrated hydrochloric acid reacts with copper to form a monovalent copper complex:
A mixture of 3 parts by volume of concentrated hydrochloric acid and 1 part by volume of concentrated nitric acid is called “aqua regia”. Aqua regia can even dissolve gold and platinum. The high oxidative activity of aqua regia is due to the presence of nitrosyl chloride and chlorine in it, which are in equilibrium with the starting substances:
Due to the high concentration of chloride ions in the solution, the metal is bound into a chloride complex, which promotes its dissolution:
Adds to sulfuric anhydride to form chlorosulfonic acid HSO3Cl:
Hydrogen chloride is also characterized by addition reactions to multiple bonds (electrophilic addition):
Receipt
In laboratory conditions, hydrogen chloride is obtained by reacting concentrated sulfuric acid with sodium chloride (table salt) with low heating:
HCl can also be prepared by hydrolysis of covalent halides such as phosphorus(V) chloride, thionyl chloride (SOCl2), and hydrolysis of carboxylic acid chlorides:
In industry, hydrogen chloride was previously obtained mainly by the sulfate method (Leblanc method), based on the interaction of sodium chloride with concentrated sulfuric acid. Currently, direct synthesis from simple substances is usually used to obtain hydrogen chloride:
Under production conditions, synthesis is carried out in special installations in which hydrogen continuously burns with an even flame in a stream of chlorine, mixing with it directly in the burner torch. This ensures a calm (without explosion) reaction. Hydrogen is supplied in excess (5 - 10%), which makes it possible to completely use the more valuable chlorine and obtain hydrochloric acid uncontaminated with chlorine.
Hydrochloric acid is prepared by dissolving hydrogen chloride gas in water.
Application
An aqueous solution is widely used for the production of chlorides, for pickling metals, cleaning the surface of vessels and wells from carbonates, processing ores, in the production of rubbers, monosodium glutamate, soda, chlorine and other products. Also used in organic synthesis. Hydrochloric acid solution has become widespread in the production of small-piece concrete and gypsum products: paving slabs, reinforced concrete products, etc.
Safety
Inhalation of hydrogen chloride can lead to coughing, suffocation, inflammation of the nose, throat and upper respiratory tract, and in severe cases, pulmonary edema, disruption of the circulatory system, and even death. Contact with skin may cause redness, pain and serious burns. Hydrogen chloride can cause serious eye burns and permanent damage.
Used as a poison during wars.
Notes
- Hydrogen chloride on the website HiMiK.ru
- Hydrochloric acid is sometimes called hydrogen chloride.
- A. A. Drozdov, V. P. Zlomanov, F. M. Spiridonov. Inorganic chemistry (in 3 volumes). T.2. - M.: Publishing Center "Academy", 2004.
Literature
- Levinsky M.I., Mazanko A.F., Novikov I.N. “Hydrogen chloride and hydrochloric acid” M.: Chemistry 1985
Links
- Hydrogen chloride: chemical and physical properties
P·o·r Chlorine-containing inorganic acids
hydrogen chloride, hydrogen chloride Wikipedia, hydrogen chloride molecule, hydrogen chloride formula, hydrogen chloride chemistry class 9, hydrochloric acid, hydrochloric acid
Hydrogen Chloride Information About
Hydrogen chloride - what is it? Hydrogen chloride is a colorless gas with a pungent odor. It dissolves easily in water, forming hydrochloric acid. The chemical formula of hydrogen chloride is HCl. It consists of a hydrogen and chlorine atom joined by a polar covalent bond. Hydrogen chloride easily dissociates in polar solvents, which provides good acidic properties of this compound. The bond length is 127.4 nm.
Physical properties
As mentioned above, in its normal state, hydrogen chloride is a gas. It is somewhat heavier than air, and also has hygroscopicity, that is, it attracts water vapor directly from the air, forming a thick cloud of vapor. For this reason, hydrogen chloride is said to “smoke” in air. If this gas is cooled, at around -85 °C it liquefies, and at -114 °C it becomes a solid. At a temperature of 1500 °C it decomposes into simple substances (based on the formula of hydrogen chloride, into chlorine and hydrogen).
A solution of HCl in water is called hydrochloric acid. It is a colorless, caustic liquid. Sometimes it has a yellowish tint due to impurities of chlorine or iron. Due to hygroscopicity, the maximum concentration at 20 °C is 37-38% by weight. Other physical properties also depend on it: density, viscosity, melting and boiling points.
Chemical properties
Hydrogen chloride itself usually does not react. Only at high temperatures (over 650 °C) does it react with sulfides, carbides, nitrides and borides, as well as transition metal oxides. In the presence of Lewis acids, it can react with boron, silicon and germanium hydrides. But its aqueous solution is much more chemically active. According to its formula, hydrogen chloride is an acid, so it has some properties of acids:
- Interaction with metals (which are in the electrochemical voltage range up to hydrogen):
Fe + 2HCl = FeCl 2 + H 2
- Interaction with amphoteric and basic oxides:
BaO + 2HCl = BaCl 2 + H 2 O
- Interaction with alkalis:
NaOH + HCl = NaCl + H2O
Interaction with some salts:
Na 2 CO 3 + 2HCl = 2NaCl + H 2 O + CO 2
- When reacting with ammonia, ammonium chloride salt is formed:
NH 3 + HCl = NH 4 Cl
But hydrochloric acid does not react with lead due to passivation. This is due to the formation of a layer of lead chloride on the surface of the metal, which is insoluble in water. Thus, this layer protects the metal from further interaction with hydrochloric acid.
In organic reactions, it can join through multiple bonds (hydrohalogenation reaction). It can also react with proteins or amines, forming organic salts - hydrochlorides. Artificial fibers, such as paper, are destroyed when interacting with hydrochloric acid. In redox reactions with strong oxidizing agents, hydrogen chloride is reduced to chlorine.
A mixture of concentrated hydrochloric and nitric acid (3 to 1 by volume) is called “aqua regia.” It is an extremely strong oxidizing agent. Due to the formation of free chlorine and nitrosyl in this mixture, aqua regia can even dissolve gold and platinum.
Receipt
Previously, in industry, hydrochloric acid was obtained by reacting sodium chloride with acids, usually sulfuric acid:
2NaCl + H 2 SO 4 = 2HCl + Na 2 SO 4
But this method is not effective enough, and the purity of the resulting product is low. Now another method is used to obtain (from simple substances) hydrogen chloride according to the formula:
H2 + Cl2 = 2HCl
To implement this method, there are special installations where both gases are supplied in a continuous flow to the flame in which the interaction occurs. Hydrogen is supplied in a slight excess so that all the chlorine reacts and does not contaminate the resulting product. Next, hydrogen chloride is dissolved in water to form hydrochloric acid.
In the laboratory, more diverse methods of preparation are possible, for example hydrolysis of phosphorus halides:
PCl 5 + H 2 O = POCl 3 + 2HCl
Hydrochloric acid can also be obtained by hydrolysis of crystalline hydrates of certain metal chlorides at elevated temperatures:
AlCl 3 6H 2 O = Al(OH) 3 + 3HCl + 3H 2 O
Hydrogen chloride is also a by-product of the chlorination reactions of many organic compounds.
Application
Hydrogen chloride itself is not used in practice, since it very quickly absorbs water from the air. Almost all of the hydrogen chloride produced goes into the production of hydrochloric acid.
It is used in metallurgy to clean the surface of metals, as well as to obtain pure metals from their ores. This occurs by converting them into chlorides, which are easily reduced. For example, titanium and zirconium are obtained. The acid is widely used in organic synthesis (hydrohalogenation reactions). Pure chlorine is also sometimes obtained from hydrochloric acid.
It is also used in medicine as a medicine mixed with pepsin. It is taken when the stomach acidity is insufficient. Hydrochloric acid is used in the food industry as an additive E507 (acidity regulator).
Safety precautions
At high concentrations, hydrochloric acid is a caustic substance. When it gets on the skin, it causes chemical burns. Inhaling hydrogen chloride gas causes coughing, suffocation, and in severe cases even pulmonary edema, which can lead to death.
According to GOST, it has the second hazard class. Hydrogen chloride is classified as a hazard category three out of four according to NFPA 704. Short-term exposure may result in serious temporary or moderate residual effects.
First aid
If hydrochloric acid gets on the skin, the wound should be washed generously with water and a weak solution of alkali or its salt (for example, soda).
If hydrogen chloride vapor gets into the respiratory tract, the victim must be taken out into fresh air and inhaled with oxygen. After this, you should gargle, wash your eyes and nose with a 2% sodium bicarbonate solution. If hydrochloric acid gets into your eyes, then you should drip them with a solution of novocaine and dicaine with adrenaline.
