20. Chlorine. Hydrogen chloride and hydrochloric acid

Chlorine (Cl) - stands in the 3rd period, in the VII group of the main subgroup of the periodic system, serial number 17, atomic mass 35.453; refers to halogens.

Physical properties: yellow-green gas with a pungent odor. Density 3.214 g/l; melting point -101 °C; boiling point -33.97 °C, At ordinary temperature, it is easily liquefied under a pressure of 0.6 MPa. Dissolving in water, it forms yellowish chlorine water. Let's well dissolve in organic solvents, especially in hexane (C6H14), in carbon tetrachloride.

Chemical properties of chlorine: electronic configuration: 1s22s22p63s22p5. There are 7 electrons in the outer level. Before the level is completed, 1 electron is needed, which chlorine accepts, showing an oxidation state of -1. There are also positive oxidation states of chlorine up to + 7. The following oxides of chlorine are known: Cl2O, ClO2, Cl2O6 and Cl2O7. All of them are unstable. Chlorine is a strong oxidizing agent. It directly reacts with metals and non-metals:

Reacts with hydrogen. Under normal conditions, the reaction proceeds slowly, with strong heating or lighting - with an explosion, according to a chain mechanism:

Chlorine interacts with alkali solutions, forming salts - hypochlorites and chlorides:

When chlorine is passed into an alkali solution, a mixture of chloride and hypochlorite solutions is formed:

Chlorine is a reducing agent: Cl2 + 3F2 = 2ClF3.

Interaction with water:

Chlorine does not interact directly with carbon, nitrogen and oxygen.

Receipt: 2NaCl + F2 = 2NaF + Cl2.

Electrolysis: 2NaCl + 2H2O = Cl2 + H2 + 2NaOH.

Finding in nature: contained in the composition of minerals: halite (rock salt), sylvin, bischofite; sea ​​water contains chlorides of sodium, potassium, magnesium and other elements.

Hydrogen chloride HCl. Physical properties: colorless gas, heavier than air, soluble in water to form hydrochloric acid.

Hydrogen chloride- it is a colorless gas heavier than air with a pungent odor, which consists in equal volumes of chlorine and hydrogen, the formula: HCl

A mixture of chlorine and hydrogen gives a violent reaction and explodes even in sunlight, forming hydrogen chloride.

Hydrogen chloride itself is not a combustible gas.

In the laboratory, you can get hydrogen chloride using concentrated sulfuric acid + table salt and heating this mixture.

Hydrogen chloride gas is highly soluble 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 is more intense.

Hydrochloric acid is widely used to clean surfaces from rust. However, this can only be done by using inhibitors (additives that slow down the reaction of the metal with the acid) so that the acid does not damage the metal itself. Salts are also obtained from acid, it is used in medicine, etc. This acid is even secreted by our stomach to digest food, but the concentration there is very small (0.2-0.5%).

Salts of this acid are called chlorides. Chlorides are mostly also soluble in water.

If you add silver nitrate (AgNO 3) to hydrochloric acid or its salt, then a white cheesy precipitate will form. This precipitate is insoluble in acids, which always makes it possible to establish the presence of chloride ions.

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hydrochloric kisselin, hydrogen chloride formula
Hydrogen chloride, hydrogen chloride(HCl) - a colorless, thermally stable gas (under normal conditions) with a pungent odor, fuming in humid air, easily soluble in water (up to 500 volumes of gas per volume of water) to form hydrochloric (hydrochloric) acid. At -85.1 °C, it condenses to a colorless, mobile liquid. At −114.22 °C, HCl becomes solid. in the solid state, hydrogen chloride exists in the form of two crystalline modifications: rhombic, stable below -174.75 ° C, and cubic.

• 1 Properties
• 2 Getting
• 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 vigorously 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, sylvin). 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).

Under the action of 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 volume parts of concentrated hydrochloric acid and 1 volume fraction of concentrated nitric acid is called aqua regia. Royal vodka is able to dissolve even 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 materials:

Due to the high concentration of chloride ions in the solution, the metal binds to the chloride complex, which contributes to its dissolution:

Adds to sulfuric anhydride, forming chlorosulfonic acid HSO3Cl:

Hydrogen chloride is also characterized by reactions of addition to multiple bonds (electrophilic addition):

Receipt

Under laboratory conditions, hydrogen chloride is obtained by acting with concentrated sulfuric acid on sodium chloride (common salt) with low heating:

HCl can also be obtained by hydrolysis of covalent halides such as phosphorus(V) chloride, thionyl chloride (SOCl2) and by 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, to obtain hydrogen chloride, direct synthesis from simple substances is usually used:

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. Thus, a calm (without explosion) course of the reaction is achieved. Hydrogen is supplied in excess (5 - 10%), which makes it possible to fully use more valuable chlorine and obtain hydrochloric acid that is not contaminated with chlorine.

Hydrochloric acid is produced by dissolving hydrogen chloride gas in water.

Application

The aqueous solution is widely used for obtaining chlorides, for etching metals, cleaning the surface of vessels, wells from carbonates, processing ores, in the production of rubbers, monosodium glutamate, soda, chlorine and other products. Also used in organic synthesis. A solution of hydrochloric acid was widely used in the production of small-piece concrete and gypsum products: paving slabs, reinforced concrete products, etc.

Security

Inhalation of hydrogen chloride can lead to coughing, choking, inflammation of the nose, throat, and upper respiratory tract, and in severe cases, pulmonary edema, circulatory problems, and even death. Contact with skin can cause redness, pain and severe burns. Hydrogen chloride can cause severe eye burns and permanent eye damage.

Used as a poison during wars.

Notes

1. Hydrogen chloride on the site HiMiK.ru
2. Hydrochloric acid is sometimes referred to as hydrogen chloride.
3. 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. "Hydrochloride and hydrochloric acid" M.: Chemistry 1985

Links

• Hydrogen chloride: chemical and physical properties

P o r Chlorinated inorganic acids

hydrogen chloride, hydrogen chloride wikipedia, hydrogen chloride molecule, hydrogen chloride formula, hydrogen chloride chemistry class 9, hydrochloric kisselin, hydrochloric acid

Hydrogen Chloride Information About

DEFINITION

Hydrogen chloride(hydrochloric acid, hydrochloric acid) - a complex substance of inorganic nature, which can exist both in liquid and in gaseous state.

In the second case, it is a colorless gas, highly soluble in water, and in the first case, it is a solution of a strong acid (35-36%). The structure of the hydrogen chloride molecule, as well as its structural formula, are shown in fig. 1. Density - 1.6391 g / l (N.O.). The melting point is - (-114.0 o C), boiling - (-85.05 o C).

Rice. 1. Structural formula and spatial structure of the hydrogen chloride molecule.

The gross formula of hydrogen chloride is HCl. As is known, the molecular mass of a molecule is equal to the sum of the relative atomic masses of the atoms that make up the molecule (the values ​​of the relative atomic masses taken from the Periodic Table of D.I. Mendeleev are rounded to integers).

Mr(HCl) = Ar(H) + Ar(Cl);

Mr(HCl) = 1 + 35.5 = 36.5.

Molar mass (M) is the mass of 1 mole of a substance. It is easy to show that the numerical values ​​of the molar mass M and the relative molecular mass M r are equal, however, the first value has the dimension [M] = g/mol, and the second is dimensionless:

M = N A × m (1 molecules) = N A × M r × 1 a.m.u. = (N A ×1 amu) × M r = × M r .

It means that the molar mass of hydrogen chloride is 36.5 g/mol.

The molar mass of a substance in the gaseous state can be determined using the concept of its molar volume. To do this, find the volume occupied under normal conditions by a certain mass of a given substance, and then calculate the mass of 22.4 liters of this substance under the same conditions.

To achieve this goal (calculation of the molar mass), it is possible to use the equation of state of an ideal gas (the Mendeleev-Clapeyron equation):

where p is the gas pressure (Pa), V is the gas volume (m 3), m is the mass of the substance (g), M is the molar mass of the substance (g / mol), T is the absolute temperature (K), R is the universal gas constant equal to 8.314 J / (mol × K).

Examples of problem solving

EXAMPLE 1

Exercise	In which of the following substances is the mass fraction of the oxygen element greater: a) in zinc oxide (ZnO); b) in magnesium oxide (MgO)?
Decision	Find the molecular weight of zinc oxide: Mr(ZnO) = Ar(Zn) + Ar(O); Mr(ZnO)=65+16=81. It is known that M = Mr, which means M(ZnO) = 81 g/mol. Then the mass fraction of oxygen in zinc oxide will be equal to: ω (O) = Ar (O) / M (ZnO) × 100%; ω(O) = 16 / 81 × 100% = 19.75%. Find the molecular weight of magnesium oxide: Mr(MgO) = Ar(Mg) + Ar(O); Mr (MgO) = 24+ 16 = 40. It is known that M = Mr, which means M(MgO) = 60 g/mol. Then the mass fraction of oxygen in magnesium oxide will be equal to: ω (O) = Ar (O) / M (MgO) × 100%; ω (O) = 16 / 40 × 100% = 40%. Thus, the mass fraction of oxygen is greater in magnesium oxide, since 40 > 19.75.
Answer	The mass fraction of oxygen is greater in magnesium oxide

EXAMPLE 2

Exercise	In which of the following compounds, the mass fraction of metal is greater: a) in aluminum oxide (Al 2 O 3); b) in iron oxide (Fe 2 O 3)?
Decision	The mass fraction of the element X in the molecule of the HX composition is calculated by the following formula: ω (X) = n × Ar (X) / M (HX) × 100%. Let us calculate the mass fraction of each element of oxygen in each of the proposed compounds (the values ​​of the relative atomic masses taken from the Periodic Table of D.I. Mendeleev will be rounded to integers). Find the molecular weight of aluminum oxide: Mr (Al 2 O 3) = 2×Ar(Al) + 3×Ar(O); Mr (Al 2 O 3) \u003d 2 × 27 + 3 × 16 \u003d 54 + 48 \u003d 102. It is known that M \u003d Mr, which means M (Al 2 O 3) \u003d 102 g / mol. Then the mass fraction of aluminum in the oxide will be equal to: ω (Al) \u003d 2 × Ar (Al) / M (Al 2 O 3) × 100%; ω (Al) \u003d 2 × 27 / 102 × 100% \u003d 54 / 102 × 100% \u003d 52.94%. Find the molecular weight of iron oxide (III): Mr (Fe 2 O 3) = 2×Ar(Fe) + 3×Ar(O); Mr (Fe 2 O 3) \u003d 2 × 56 + 3 × 16 \u003d 112 + 48 \u003d 160. It is known that M \u003d Mr, which means M (Fe 2 O 3) \u003d 160 g / mol. Then the mass fraction of iron in the oxide will be equal to: ω (O) \u003d 3 × Ar (O) / M (Fe 2 O 3) × 100%; ω (O) = 3×16 / 160 × 100% = 48 / 160× 100% = 30%. Thus, the mass fraction of metal is greater in aluminum oxide, since 52.94 > 30.
Answer	The mass fraction of metal is greater in aluminum oxide

Chlorine- an element of the 3rd period and VII A-group of the Periodic system, serial number 17. The electronic formula of the atom is [ 10 Ne] 3s 2 3p 5, the characteristic oxidation states are 0, -I, +I, +V and +VII. The most stable state is Cl-I. Chlorine oxidation state scale:

Chlorine has a high electronegativity (2.83) and exhibits non-metallic properties. It is a part of many substances - oxides, acids, salts, binary compounds.

In nature - twelfth by chemical abundance, the element (fifth among non-metals). It occurs only in a chemically bound form. The third element in content in natural waters (after O and H), especially a lot of chlorine in sea water (up to 2% by weight). A vital element for all organisms.

Chlorine Cl 2 . Simple substance. Yellow-green gas with a pungent, suffocating odour. The Cl 2 molecule is nonpolar and contains a CI–Cl σ-bond. Thermally stable, non-combustible in air; mixture with hydrogen explodes in the light (hydrogen burns in chlorine):

It is highly soluble in water, undergoes dismutation in it by 50% and completely - in an alkaline solution:

A solution of chlorine in water is called chlorine water, in the light, acid HClO decomposes into HCl and atomic oxygen O 0, therefore, “chlorine water” must be stored in a dark bottle. The presence of HClO acid in "chlorine water" and the formation of atomic oxygen explain its strong oxidizing properties: for example, many dyes become colorless in wet chlorine.

Chlorine is a very strong oxidizing agent with respect to metals and non-metals:

Reactions with compounds of other halogens:

a) Cl 2 + 2KBr (p) = 2KCl + Br 2 (boiling)

b) Cl 2 (week) + 2KI (p) = 2KCl + I 2 ↓

3Cl 2 (ex.) + ZN 2 O + KI \u003d 6HCl + KIO 3 (80 ° C)

Qualitative reaction– interaction of Cl 2 deficiency with KI (see above) and detection of iodine by blue coloration after addition of starch solution.

Receipt chlorine in industry:

and in laboratories:

4НCl (conc.) + MnO 2 = Cl 2 + MnCl 2 + 2Н 2 O

(similarly with the participation of other oxidizing agents; see the reactions for HCl and NaCl for more details).

Chlorine is a product of the main chemical industry, used to produce bromine and iodine, chlorides and oxygen-containing derivatives, for bleaching paper, as a disinfectant for drinking water. Poisonous.

Hydrogen chloride HCl. Anoxic acid. A colorless gas with a pungent odor, heavier than air. The molecule contains a covalent σ-bond H - Cl. Thermally stable. Let's very well dissolve in water; dilute solutions are called hydrochloric acid, and a fuming concentrated solution (35–38%) - hydrochloric acid(the name was given by the alchemists). Strong acid in solution, neutralized by alkalis and ammonia hydrate. A strong reducing agent in a concentrated solution (due to Cl ‑I), a weak oxidizing agent in a dilute solution (due to H I). An integral part of "royal vodka".

A qualitative reaction to the Cl - ion is the formation of white precipitates of AgCl and Hg 2 Cl 2, which are not transferred into solution by the action of dilute nitric acid.

Hydrogen chloride serves as a raw material in the production of chlorides, organochlorine products, is used (in the form of a solution) in the etching of metals, the decomposition of minerals and ores.

Equations of the most important reactions:

HCl (dil.) + NaOH (dil.) \u003d NaCl + H 2 O

HCl (razb.) + NH 3 H 2 O \u003d NH 4 Cl + H 2 O

4HCl (conc., horizon) + MO 2 \u003d MCl 2 + Cl 2 + 2H 2 O (M \u003d Mn, Pb)

16HCl (conc., horizon) + 2KMnO 4(t) = 2MnCl 2 + 5Cl 2 + 8H 2 O + 2KCl

14HCl (conc.) + K 2 Cr 2 O 7 (t) \u003d 2CrCl 3 + ZCl 2 + 7H 2 O + 2KCl

6HCl (conc.) + KClO 3 (t) \u003d KCl + ZCl 2 + 3H 2 O (50–80 ° C)

4HCl (conc.) + Ca(ClO) 2(t) = CaCl 2 + 2Cl 2 | + 2H 2 O

2HCl (razb.) + M \u003d MCl 2 + H 2 (M \u003d Fe, Zn)

2HCl (razb.) + MSO 3 \u003d MCl 2 + CO 2 + H 2 O (M \u003d Ca, Ba)

HCl (razb.) + AgNO 3 = HNO 3 + AgCl ↓

Receipt HCl in industry - combustion of H 2 in Cl 2 (see), in the laboratory - displacement from chlorides with sulfuric acid:

NaCl (t) + H 2 SO 4 (conc.) = NaHSO 4 + HCl(50°C)

2NaCl (t) + H 2 SO 4 (conc.) = Na 2 SO 4 + 2НCl(120°C)