What is ammonia? Formula and properties of ammonia. Ammonia. Physical and chemical properties. Getting and using

The volatile characteristic hydrogen compound of nitrogen is ammonia. In terms of importance in the inorganic chemical industry and inorganic chemistry, ammonia is the most important hydrogen compound of nitrogen. By its chemical nature, it is hydrogen nitride H 3 N. In the chemical structure of ammonia, the sp 3 hybrid orbitals of the nitrogen atom form three σ-bonds with three hydrogen atoms, which occupy three vertices of a slightly distorted tetrahedron.

The fourth vertex of the tetrahedron is occupied by the lone electron pair of nitrogen, which ensures the chemical unsaturation and reactivity of ammonia molecules, as well as a large electric moment of the dipole.

Under normal conditions, ammonia is a colorless gas with a pungent odor. It is toxic: it irritates mucous membranes, and acute poisoning causes eye damage and pneumonia. Due to the polarity of the molecules and the rather high dielectric constant, liquid ammonia is a good solvent. Alkali and alkaline earth metals, sulfur, phosphorus, iodine, many salts and acids dissolve well in liquid ammonia. In terms of solubility in water, ammonia is superior to any other gas. This solution is called ammonia water, or ammonia. The excellent solubility of ammonia in water is due to the formation of intermolecular hydrogen bonds.

Ammonia has the main properties:

Interaction of ammonia with water:

NH 3 +HOH ⇄ NH 4 OH ⇄ NH 4 + +OH -

Interaction with hydrogen halides:

NH 3 + HCl ⇄NH 4 Cl

Interaction with acids (as a result, medium and acidic salts are formed):

NH 3 + H 3 PO 4 → (NH 4) 3 PO 4 ammonium phosphate

NH 3 + H 3 PO 4 → (NH 4) 2 HPO 4 ammonium hydrogen phosphate

NH 3 + H 3 PO 4 → (NH 4) H 2 PO 4 ammonium dihydrogen phosphate

Ammonia interacts with salts of some metals to form complex compounds - ammoniates:

CuSO 4 + 4NH 3 → SO 4 copper tetraammine sulfate (II)

AgCl+ 2NH 3 → Cl diammine silver chloride (I)

All of the above reactions are addition reactions.

Redox properties:

In the ammonia molecule NH 3, nitrogen has an oxidation state of -3, therefore, in redox reactions, it can only donate electrons and is only a reducing agent.

Ammonia restores some metals from their oxides:

2NH 3 + 3CuO → N 2 + 3Cu + 3H 2 O

Ammonia in the presence of a catalyst is oxidized to nitrogen monoxide NO:

4NH 3 + 5O 2 → 4NO+ 6H 2 O

Ammonia is oxidized by oxygen without a catalyst to nitrogen:

4NH 3 + 3O 2 → 2N 2 + 6H 2 O

21. Hydrogen compounds of halogens. 22. Hydrohalic acids.

Hydrogen halides are colorless gases with a pungent odor, easily soluble in water. Hydrogen fluoride is miscible with water in any ratio. The high solubility of these compounds in water makes it possible to obtain concentrated solutions.

When dissolved in water, hydrogen halides dissociate as acids. HF refers to weakly dissociated compounds, which is explained by the special strength of the bond. The remaining solutions of hydrogen halides are among the strong acids. HF - hydrofluoric (hydrofluoric) acid HCl - hydrochloric (hydrochloric) acid HBr - hydrobromic acid HI - hydroiodic acid

The strength of acids in the series HF - HCl - HBr - HI increases, which is explained by a decrease in the same direction of the binding energy and an increase in the internuclear distance. HI is the strongest of the hydrohalic acids.

Polarizability increases due to the fact that water polarizes more of the bond, whose length is longer. Salts of hydrohalic acids are respectively named as fluorides, chlorides, bromides, iodides.

Chemical properties of hydrohalic acids

In dry form, hydrogen halides do not act on most metals.

1. Aqueous solutions of hydrogen halides have the properties of oxygen-free acids. Vigorously interact with many metals, their oxides and hydroxides; metals that are in the electrochemical series of voltages of metals after hydrogen are not affected. Interact with some salts and gases.

Hydrofluoric acid destroys glass and silicates:

SiO2+4HF=SiF4+2Н2O

Therefore, it cannot be stored in glassware.

2. In redox reactions, hydrohalic acids behave as reducing agents, and the reducing activity in the series Cl-, Br-, I- increases.

Receipt

Hydrogen fluoride is produced by the action of concentrated sulfuric acid on fluorspar:

CaF2+H2SO4=CaSO4+2HF

Hydrogen chloride is obtained by direct interaction of hydrogen with chlorine:

This is a synthetic way to get.

The sulfate method is based on the reaction of concentrated sulfuric acid with NaCl.

With slight heating, the reaction proceeds with the formation of HCl and NaHSO4.

NaCl+H2SO4=NaHSO4+HCl

At a higher temperature, the second stage of the reaction proceeds:

NaCl+NaHSO4=Na2SO4+HCl

But HBr and HI cannot be obtained in a similar way, because their compounds with metals, when interacting with concentrated sulfuric acid, are oxidized, tk. I- and Br- are strong reducing agents.

2NaBr-1+2H2S+6O4(c)=Br02+S+4O2+Na2SO4+2H2O

Hydrogen bromide and hydrogen iodide are obtained by hydrolysis of PBr3 and PI3: PBr3+3Н2O=3HBr+Н3PO3 PI3+3Н2О=3HI+Н3РO3

Hydrogen, under normal conditions - a colorless gas with a pungent characteristic odor (the smell of ammonia)

• Halogens (chlorine, iodine) form dangerous explosives with ammonia - nitrogen halides (nitrogen chloride, nitrogen iodide).

• With haloalkanes, ammonia enters into a nucleophilic addition reaction, forming a substituted ammonium ion (a method for obtaining amines):

• With carboxylic acids, their anhydrides, acid halides, esters and other derivatives gives amides. With aldehydes and ketones - Schiff bases, which can be reduced to the corresponding amines (reductive amination).

• At 1000 °C, ammonia reacts with coal, forming hydrocyanic acid HCN and partially decomposing into nitrogen and hydrogen. It can also react with methane, forming the same hydrocyanic acid:

Name history

Ammonia (in European languages, its name sounds like "ammoniac") owes its name to the Ammon oasis in North Africa, located at the crossroads of caravan routes. In hot climates, urea (NH 2) 2 CO contained in animal waste decomposes especially quickly. One of the degradation products is ammonia. According to other sources, ammonia got its name from the ancient Egyptian word amonian. So called people worshiping the god Amun. During their ritual rites, they sniffed ammonia NH 4 Cl, which, when heated, evaporates ammonia.

Liquid ammonia

Liquid ammonia, although to a small extent, dissociates into ions (autoprotolysis), in which its similarity with water is manifested:

The self-ionization constant of liquid ammonia at −50 °C is approximately 10 −33 (mol/l)².

The metal amides resulting from the reaction with ammonia contain the negative NH 2 − ion, which is also formed during the self-ionization of ammonia. Thus, metal amides are analogues of hydroxides. The reaction rate increases when going from Li to Cs. The reaction is greatly accelerated in the presence of even small impurities of H 2 O.

Metal-ammonia solutions have metallic electrical conductivity; in them, metal atoms decay into positive ions and solvated electrons surrounded by NH 3 molecules. Metal-ammonia solutions containing free electrons are the strongest reducing agents.

complex formation

Due to their electron-donating properties, NH 3 molecules can enter complex compounds as a ligand. Thus, the introduction of an excess of ammonia into solutions of salts of d-metals leads to the formation of their amino complexes:

Complexation is usually accompanied by a change in the color of the solution. So, in the first reaction, the blue color (CuSO 4) turns into dark blue (color of the complex), and in the second reaction, the color changes from green (Ni (NO 3) 2) to blue-violet. The strongest complexes with NH 3 form chromium and cobalt in the +3 oxidation state.

Biological role

Ammonia is the end product of nitrogen metabolism in humans and animals. It is formed during the metabolism of proteins, amino acids, and other nitrogenous compounds. It is highly toxic to the body, so most of the ammonia during the ornithine cycle is converted by the liver into a more harmless and less toxic compound - urea (urea). Urea is then excreted by the kidneys, and some of the urea can be converted by the liver or kidneys back into ammonia.

Ammonia can also be used by the liver for the reverse process - the resynthesis of amino acids from ammonia and keto analogs of amino acids. This process is called "reductive amination". So from sorrel acetic acid it turns out aspartic, from α-ketoglutaric - glutamine, etc.

Physiological action

According to the physiological effect on the body, it belongs to the group of substances with an asphyxiant and neurotropic effect, which, when inhaled, can cause toxic pulmonary edema and severe damage. nervous system. Ammonia has both local and resorptive effects.

Ammonia vapor strongly irritates the mucous membranes of the eyes and respiratory organs, as well as the skin. This is a person and perceives as a pungent smell. Ammonia vapors cause profuse lacrimation, pain in the eyes, chemical burns of the conjunctiva and cornea, loss of vision, coughing fits, redness and itching of the skin. When liquefied ammonia and its solutions come into contact with the skin, a burning sensation occurs, a chemical burn with blisters and ulcerations is possible. In addition, liquefied ammonia absorbs heat during evaporation, and frostbite of varying degrees occurs when it comes into contact with the skin. The smell of ammonia is felt at a concentration of 37 mg/m³.

Application

Ammonia is one of the most important products of the chemical industry, its annual world production reaches 150 million tons. Mainly used for the production of nitrogen fertilizers (ammonium nitrate and sulfate, urea), explosives and polymers, nitric acid, soda (ammonia method) and other products of the chemical industry. Liquid ammonia is used as a solvent.

Consumption rates per ton of ammonia

The production of one ton of ammonia in Russia consumes an average of 1200 nm³ natural gas, in Europe - 900 nm³.

Belarusian "Grodno Azot" consumes 1200 Nm³ of natural gas per tonne of ammonia, after the modernization the consumption is expected to decrease to 876 Nm³.

Ukrainian producers consume from 750 Nm³ to 1170 Nm³ of natural gas per tonne of ammonia.

UHDE technology claims consumption of 6.7 - 7.4 Gcal of energy resources per ton of ammonia.

Ammonia in medicine

For insect bites, ammonia is applied externally in the form of lotions. A 10% aqueous ammonia solution is known as ammonia.

Side effects are possible: with prolonged exposure (inhalation use), ammonia can cause reflex respiratory arrest.

Topical application is contraindicated in dermatitis, eczema, and other skin diseases, as well as with open traumatic injuries of the skin.

In case of accidental damage to the mucous membrane of the eye, rinse with water (for 15 minutes every 10 minutes) or with a 5% solution of boric acid. Oils and ointments are not used. With the defeat of the nose and pharynx - 0.5% solution of citric acid or natural juices. In case of ingestion, drink water, fruit juice, milk, preferably 0.5% citric acid solution or 1% acetic acid solution until the contents of the stomach are completely neutralized.

Interaction with other drugs is unknown.

Ammonia producers

Ammonia producers in Russia

Russia accounts for about 9% of the world's ammonia output. Russia is one of the world's largest exporters of ammonia. About 25% of the total ammonia production is exported, which is about 16% of world exports.

Ammonia producers in Ukraine

• Jupiter's clouds are made up of ammonia.

see also

Notes

Links

• //
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
• // Encyclopedic Dictionary of Brockhaus and Efron: In 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.

Literature

• Akhmetov N. S. General and inorganic chemistry. - M.: Higher school, 2001.

10% aqueous solution ammonia . Concentration active substance in a liter of solution - 440 ml.

As an auxiliary component, the composition of the preparation includes purified water (in a volume of up to 1 liter).

Release form

Solution for inhalation and external use 10%. Available in 10 ml dropper bottles, 40 and 100 ml bottles.

It is a clear, volatile liquid, colorless and with a pungent odor.

pharmachologic effect

annoying , antiseptic , analeptic , emetic .

Pharmacodynamics and pharmacokinetics

The agent has an irritating effect on the exteroreceptors of the skin and provokes a local release prostaglandins , kinins and histamine . Acts as a liberator in the spinal cord enkephalins and endorphins , which block the flow of pain impulses from pathological foci.

When it enters the upper respiratory tract, it interacts with the endings of the trigeminal nerve and reflexively excites the respiratory center. A concentrated solution causes colliquation (softening and dissolution) of microbial cell proteins.

With any method of administration, it is quickly eliminated from the body (mainly by the bronchial glands and lungs). It reflexively affects the tone of the vascular walls and the activity of the heart.

At the site of application, when applied externally, it dilates blood vessels, improves tissue regeneration and trophism, and also stimulates the outflow of metabolites.

When the skin is irritated, it causes similar reflexes in the segmentally located muscles and internal organs, contributing to the restoration of impaired functions and structures.

It suppresses the focus of excitation, which supports the pathological process, reduces muscle tension, hyperalgesia, relieves vasospasm, thus providing a distracting effect.

With prolonged contact, it burns the mucous membranes and skin, which is accompanied by tissue hyperemia, the development of swelling and soreness.

Reception per os in small concentrations stimulates the secretion of the glands, acting on the vomiting center, reflexively increases its excitability and causes vomiting.

The drug does not enter the bloodstream.

Indications for use

Inhalation is used to stimulate breathing during fainting.

Ingestion is indicated to stimulate vomiting (in diluted form).

Externally used to disinfect the doctor's hands before surgical operation, in the form of lotions for neuralgia, insect bites, myositis.

Contraindications

Intolerance.

Topical application is contraindicated in skin diseases.

Side effects: the effect on the human body of vapors and ammonia solution

In the case of taking the solution in undiluted form, it is possible alimentary canal burns (esophagus and stomach). Inhalation of the drug in high concentrations can provoke reflex respiratory arrest.

Ammonia solution: instructions for use

The instructions for use of ammonia indicate that the dose of the drug is selected individually, depending on the indications.

In surgical practice, as a means for washing hands, the solution is used according to the Spasokukotsky-Kochergin method, diluting 50 ml of the solution in 1 liter of boiled water (warm).

When used to stimulate breathing, the solution is applied to gauze or cotton. For insect bites, it is used in the form of lotions.

The use of ammonia in horticulture

The use of ammonia for plants is quite diverse: it is used for aphids, for processing onions from onion flies, for feeding plants.

Ammonia from aphids is used at the rate of 2 tbsp. spoons for 10 liters of water. A little washing powder should also be added to the bucket - this will provide better adhesion. The solution is used for spraying plants.

Ammonia as a fertilizer: in this case, 50 ml of solution should be taken per 4 liters of water. The tool is not only a good top dressing for indoor and garden plants, but also allows you to get rid of midges and mosquitoes.

For watering onions, dilute 1-2 tbsp. spoons of ammonia. It is recommended to water the plants with such a remedy from the moment of planting until the end of June.

How to clean gold?

There are several ways to clean gold with ammonia.

You can mix 1 teaspoon of alcohol with a glass of water and 1 tbsp. spoon of any detergent, or you can add to water (200 ml), ammonia (1 teaspoon), (30 ml), half a teaspoon of liquid detergent.

In the first case, the jewelry is placed in a cleaning solution for an hour or two, in the second - for 15 minutes. After cleaning, the gold should be rinsed in water and wiped dry with a napkin.

How to clean silver?

To clean silver, ammonia is diluted with water in a ratio of 1:10 (1 part alcohol to 10 parts water). Silver items are left in the solution for several hours, then rinsed in water and wiped with a soft cloth.

For regular cleaning of silver, a soapy solution is used, to which a small amount of ammonia is added.

Ammonia from cockroaches and ants

To combat ants, 100 ml of the solution is diluted in a liter of water and furniture in the kitchen is washed with this product. To get rid of cockroaches with ammonia, wash the floor.

Ammonia for heels

As a means to soften rough skin of the feet, ammonia is mixed with glycerin (1: 1). The product is applied to the feet before going to bed, and socks are put on top.

Overdose. Effects of ammonia vapor on the human body

An overdose causes an increase in the manifestations of adverse reactions. So, the effect on the human body of a high dose of ammonia solution when taken orally is manifested:

• vomiting with a characteristic smell of ammonia;
• diarrhea with tenesmus (false painful urge to defecate);
• swelling of the larynx;
• runny nose;
• cough;
• arousal;
• convulsions;
• collapse .

In some cases it is possible fatal outcome (patient dies when taking 10-15 g ammonium hydroxide ).

Treatment for overdose is symptomatic.

Sometimes people are interested in what will happen if you drink ammonia. You should be aware that oral administration of the solution in its pure form can provoke severe burns of the digestive canal.

Symptoms of ammonia poisoning

Human exposure to ammonia by inhalation of its vapors manifests itself in the form of irritation of the mucous membranes of the eyes and respiratory tract. In this case, the intensity of irritation depends on the concentration of the gas.

Signs of ammonia poisoning:

• profuse lacrimation;
• salivation;
• shortness of breath;
• increased sweating;
• hyperemia of the face;
• feeling of heaviness and tightness in the chest;
• chest pain;
• whooping cough;
• sneezing
• runny nose;
• swelling of the larynx and spasm in the vocal cords;
• anxiety;
• suffocation;
• convulsions;
• loss of consciousness.

With prolonged exposure, ammonia vapors provoke severe muscle weakness, blood circulation is disturbed in a person, symptoms appear that indicate respiratory distress, as well as soreness, severe burning and swelling of the skin.

Regularly repeated exposure to ammonia leads to systemic disorders that manifest themselves eating disorders , deafness , catarrh of the upper respiratory tract , heart failure , death .

For protection against harmful effects ammonia, rinse the face and unprotected skin with plenty of water and cover the face with a respirator (gauze bandage or gas mask) as soon as possible. It is good if the respirator or bandage used is soaked in water with citric acid (2 teaspoons per glass of water).

Be aware that liquid ammonia causes severe burns. For this reason, it is transported in yellow-painted steel cylinders, special tankers, road and rail tankers.

What to do in the event of an ammonia release?

Upon receipt of information about the leakage of ammonia, you should protect your skin and respiratory organs and leave the emergency area in the direction that will be indicated in the message on radio or television.

From the zone of chemical damage, you need to go to the side perpendicular to the direction of the wind.

In case of fire, it is forbidden to approach the source of ignition. Ammonia containers should be cooled from as far away as possible. For extinguishing use air-mechanical foam or sprayed water.

If there is no way to get out, an emergency sealing of the room should be made. Having got out of the danger zone, they take off their outer clothing (things are left on the street), take a shower, rinse the nasopharynx and eyes with water.

In case of an accident, take cover in the lower floors of the building.

First aid for poisoning

In case of poisoning, the victim should be taken out of the affected area. In cases where this is not possible, provide access to oxygen.

The mouth, throat and nasal cavity are washed with water for 15 minutes, the eyes are instilled with a 0.5% solution and, if necessary, additionally covered with a bandage. For greater effectiveness of rinsing, glutamic or citric acid can be added to the water.

Even with a slight degree of poisoning over the next 24 hours, the patient should be provided with absolute rest.

If a substance enters an open area of ​​​​the body, it is abundantly washed with water and covered with a bandage.

If ammonia enters the alimentary canal, it is necessary to wash the stomach.

Poisoning of any degree requires an appeal to a medical facility and - if the doctor deems it necessary - subsequent hospitalization.

After completion of the course of treatment, the patient may retain certain neurological disorders, for example, loss of memory of individual events and facts, tics with various clinical manifestations, hearing loss and pain threshold. A frequent outcome is clouding of the lens and cornea of ​​​​the eye.

Ammonia: ways of neutralization in the body

The main route of substance binding is urea biosynthesis, which occurs in the ornithine cycle in liver cells. As a result of this synthesis, urea - a substance that is not harmful to the body.

Ammonia is also transported in the blood as glutamine , which is a non-toxic neutral compound and easily passes through cell membranes.

Another of its transport forms is formed in the muscles alanine .

Interaction

Neutralizes the action of acids.

Terms of sale

Non-prescription drug.

Storage conditions

Stored under normal conditions.

Shelf life

24 months.

special instructions

What is ammonia? Characteristics, physical and chemical properties of ammonia

Ammonia or hydrogen nitride (NH3) is a colorless gas (like hydrogen, ether, oxygen). The substance has a sharp irritating odor and is released into the atmosphere with the formation of smoke. The name of the substance Latin- Ammonium.

The molar mass is 17.0306 g/mol. MPC r.z. is 20 mg/m3. Given this parameter, ammonia is classified as a low-hazard substance (hazard class IV).

NH3 is extremely soluble in water: at 0°C, about 1.2 thousand volumes of this substance dissolve in one volume of water, and about 700 volumes at a temperature of 20°C.

It has the properties of alkalis and bases.

Used as a refrigerant for refrigeration equipment. R717 is marked, where R stands for “refrigerant” (Refrigerant), “7” indicates the type of refrigerant (in the specific case that ammonia is not an organic substance), the last 2 digits are molecular mass substance used.

In liquid hydrogen nitride, the molecules form hydrogen bonds. The dielectric constant, conductivity, viscosity and density of liquid NH3 are lower than those of water (the substance is 7 times less viscous than water), the boiling point of the substance tbp is -33.35°C, it begins to melt at a temperature of -77.70°C

Like water, liquid NH3 is a highly associated substance due to the formation of hydrogen bonds.

The substance practically does not pass electric current and dissolves many organic and inorganic compounds.

In solid form, NH3 has the form of colorless crystals with a cubic lattice.

The decomposition of hydrogen nitride into nitrogen and hydrogen becomes noticeable at temperatures exceeding 1200-1300°C, in the presence of catalysts - at temperatures above 400°C.

In air, ammonia does not burn, under other conditions, namely in pure oxygen, it ignites and burns with a yellow-green flame. When a substance is burned in an excess of oxygen, nitrogen and water vapor are formed.

The combustion reaction of ammonia is described by the following equation: 4NH3 + 3O2= 2N2 + 6H2O.

The catalytic oxidation of NH3 at a temperature of 750-800°C makes it possible to obtain nitric acid (the method is used for the industrial production of HNO3).

Process steps:

• catalytic oxidation with oxygen to NO;
• conversion of NO to NO2;
• absorption of a mixture of NO2 with O2 by water (dissolving nitric oxide in water and obtaining acid);
• purification of gases escaping into the atmosphere from nitrogen oxides.

The reaction of ammonia with water produces ammonia hydrate (ammonia water or caustic ammonia). The chemical formula of the hydrate is NH3 H2O.

How is caustic ammonia obtained in industry? In industry, the synthesis of an ammonia solution with a concentration of 25% is carried out by saturating water with ammonia, which is formed as a result of coal coking in a coke oven, or with synthetic gaseous ammonia.

What is ammonia water used for? Nitrogen fertilizers, soda, dyes are obtained from aqueous solutions of ammonia.

Ammonia: obtained from nitric acid in the laboratory

To obtain NH3 from HNO3, place the test tube in a tripod in an almost horizontal position, but in such a way that acid does not flow out of it.

A few drops of HNO3 are poured into the bottom of the test tube and a few pieces of zinc or iron filings are put into it with tweezers. At the opening of the test tube, the reduced iron should be placed in this way (in such a way that it does not come into contact with nitric acid).

The test tube must be closed with a stopper with a drain tube and slightly heated. Heating will increase the rate of release of ammonia.

What does ammonia react with?

Ammonia reacts with organic substances. The reaction products of ammonia with α-chlorosubstituted carboxylic acids are artificial amino acids.

As a result of the reaction, hydrogen chloride (HCl gas) is released, which, when combined with an excess of ammonia, forms (or ammonia NH4Cl).

A large number of complex compounds contain ammonia as a ligand.

Ammonium salts are colorless solids with a crystal lattice. Almost all of them are soluble in water, and they have the same properties as the metal salts known to us.

The product of their interaction with alkalis is ammonia:

NH4Cl + KOH = KCl + NH3 + H2O

The reaction described by the formula, if indicator paper is additionally used, is qualitative reaction on ammonium salts. The latter interact with acids and other salts.

Some ammonium salts evaporate (sublimate) when heated, while others decompose.

NH3 is a weak base, therefore, the salts formed by it in an aqueous solution undergo hydrolysis.

Weaker bases than ammonia are aromatic amines, derivatives of NH3, in which hydrogen atoms are replaced by hydrocarbon radicals.

Reactions of ammonia with acids

Addition of concentrated NH3 solution of hydrochloric acid accompanied by the formation of white smoke and the release of ammonium chloride NH4Cl (ammonia).

The reaction of sulfuric acid and ammonia produces white crystals of (NH4)2SO4 - ammonium sulfate.

If nitric acid is added to NH3, white ammonium nitrate NH4 NO3 is formed.

When chloroacetic acid reacts with NH3, the chlorine atom is replaced by an amino group, and as a result, aminoacetic acid is formed.

If NH3 is passed through hydrobromic acid, ammonium bromide is formed (the reaction is described by the formula - HBr + NH3 = NH4Br).

Ammonia: heavier or lighter than air?

Compared to air, NH3 has almost half the density, so its vapor always rises. However, under certain conditions, an ammonia aerosol can form - a suspension of droplets of this substance in a gas. This aerosol is usually heavier than air and therefore more dangerous than NH3 gas.

Is hydrogen nitride a complex or simple substance?

Hydrogen nitride is formed by atoms of different elements, therefore it is a complex inorganic compound.

Molecular structure of ammonia

Ammonia is characterized by a crystal lattice of polar molecules, between which the so-called van der Waals forces . There are 3 chemical bonds in the hydrogen nitride molecule; they are formed according to the covalent polar mechanism.

The molecule looks like a trigonal pyramid, on top of which there is a nitrogen atom (the oxidation state of nitrogen in NH3 is “-3”).

Industrial method for obtaining ammonia

Getting ammonia in industry is an expensive and labor-intensive process. Industrial synthesis is based on the production of NH3 from nitrogen and hydrogen under pressure, in the presence of a catalyst and at high temperatures.

Sponge iron activated by aluminum and potassium oxides is used as a catalyst in the production of NH3 in industry. Industrial plants in which synthesis is carried out are based on the circulation of gases.

The reacted gas mixture, which contains NH3, is cooled, after which NH3 condenses and separates, and hydrogen and nitrogen that have not reacted with nitrogen with a new portion of gases are again fed to the catalyst.

There was also a presentation on the joint production of ammonia and methanol in industry.

Current GOSTs, in accordance with which hydrogen nitride is produced:

• technical liquid ammonia, anhydrous ammonia - GOST 6221-90;
• aqueous ammonia - GOST 3760-79;
• technical ammonia water - GOST 9-92.

The ammonia synthesis reaction can be characterized as follows: ammonia is formed as a product of a compound reaction occurring in the gas phase - direct, catalytic, exothermic, reversible, redox.

Substance disposal

NH3 is disposed of in a selective way to recover valuable substances for recycling, and in a way that allows the use of waste waste as a raw material for the production of other materials.

What is ammonia? Chemical formula of ammonia

Ammonia is a 10% aqueous ammonia solution. The formula of the substance is NH4OH. The Latin name is Solutio Ammonii caustici seu Ammonium causticum solutum.

Ammonia has found application in everyday life as a stain remover, a means for cleaning coins, dishes, plumbing, furniture, jewelry made of silver and gold. In addition, it is used for dyeing fabrics, fighting aphids, onion secretive proboscis, onion flies, ants and cockroaches, washing windows, and caring for rough skin on the feet.

The reaction of ammonia with allows you to get a very unstable adduct, which has the form of dry crystals, which is often used as a spectacular experiment.

Ammonia is ammonia?

Some believe that ammonia and ammonia are one and the same. However, this opinion is erroneous. Ammonia solution is ammonia or, in other words, an aqueous solution of ammonium hydroxide.

BUT ammonia is an ammonium salt, a slightly hygroscopic crystalline powder white color and odorless, which evaporates hydrogen nitride (ammonia) when heated. Its formula is NH4Cl.

Wikipedia indicates that the substance is used as a fertilizer (it is applied as a top dressing to alkaline and neutral soils under crops that are weakly responsive to excess chlorine - rice, corn, sugar beet), as food additive E510, flux for soldering, electrolyte components in galvanic cells and fast fixer in photography, smoke generator.

In the laboratory, ammonia is used for lysis erythrocytes , use in medicine is advisable to enhance the action diuretics and removal of edema of cardiac origin.

Precautionary measures

Topical application is possible only on intact skin.

In case of accidental contact with the mucous membrane of the eye, the eyes are washed with plenty of water (at least 15 minutes) or a solution of boric acid (3%). Oils and ointments in this case are contraindicated.

In the case of taking the Ammonia Solution inside, you should drink until it is completely neutralized. fruit juices, water, warm milk with soda or mineral water, a solution of citric (0.5%) or acetic (1%) acid.

In case of damage to the respiratory organs, Fresh air and warm water inhalations with the addition of citric acid or vinegar, with suffocation - oxygen.

What do the smell of ammonia in the urine and the ammonia smell of sweat indicate? .

You should know about serious evidence of the smell of ammonia from the mouth.

In women, odorous discharge is possible during menopause and pregnancy (if the pregnant woman drinks little fluid and / or takes various medications and supplements).

If your sweat smells like ammonia, it could be , , urinary incontinence, liver problems, the presence of bacteria that can provoke peptic ulcer. Another one possible reason body odor - adherence to a protein diet.

Everyone knows how ammonia smells, so if a characteristic smell appears (especially if the urine smells like a child) or an ammonia taste in the mouth, you should consult a doctor who will accurately determine the cause of this phenomenon and take the necessary measures.

For kids

In pediatrics, it is used from the age of 3.

During pregnancy

During pregnancy and lactation, use is allowed only in situations where the benefit to the woman's body outweighs the potential risk to the child.

In most cases, pregnant women try not to use ammonia in any form. Paint for pregnant women should also not contain this substance. The following ammonia-free hair dyes can be included in the list of the most suitable products for pregnant women:

• Igor Schwarzkopf (Schwarzkopf Igora Vibrance);
• paints from the Garnier palette (Garnier Color & Shine);
• Estelle paint, the palette of which has 140 shades;
• paint without ammonia from the Matrix Color Sync palette;
• paint Kutrin.

Quite a few good reviews and L'Oreal ammonia-free paint (L'Oreal Professionnel LUO COLOR). However, there are women who continue to use ammonia hair dye during pregnancy.

Chemical reagents, laboratory equipment and devices are the main components of any laboratory. Regardless of the importance of properties and effects, chemicals have always been and will be the basis of all laboratory research, experiments or experiments. Their huge number gives an extensive field for activity to many chemists and pharmacologists. When combined, they can turn into both harmless and poisonous substances that can cause serious harm. Although such chemical reagents as crystalline iodine, nitric acid, aqueous ammonia are dangerous, their use in laboratory practice is of particular importance.

Definition

(in Hebrew languages ​​\u200b\u200b-“ammoniac”) is a colorless gas whose smell is familiar to everyone, even those who are very far from chemistry. It is extremely sharp, specific, reminiscent of the smell of ammonia, which can cause lacrimation. Ammonia is very toxic, twice as light as air, the mixture with which is explosive. It mixes well with alcohol and some other organic solvents in all proportions. At a temperature of 10 °C, it condenses into a liquid boiling at 33.7 °C. This chemical reagent is easily soluble in water with active heat release. This solution is called ammonia water or ammonia water. AT Food Industry- as additive E527.

Ammonia solution is not compatible with:
- organic acids;
- salts of valent metals;
- starch;
- salts of mercury;
- iodine, etc.

History of the discovery of ammonia

Translated from Greek, it means ammon salt, as ammonia was called in ancient times. Ammonia was discovered by the British chemist D. Priestley, who is known as the discoverer of oxygen and carbon dioxide. It was he who called this gas "alkaline air or volatile alkali", since an aqueous solution of ammonia had all the properties and signs of alkali. Thanks to the French chemist Berthollet, he received the official term "ammonia". This definition is used in many Western European languages.

Ammonia stripper

The main objective of this laboratory equipment is the distillation and stripping of ammonia with steam, the measurement of the mass fraction of protein in pasteurized, sterilized or raw milk, fermented milk drinks.
This apparatus consists of:
- conical flask;
- drip funnels with a tap;
- an adapter made of laboratory glass;
- Kjeldahl glass flask;
- T-shaped, curved connecting and rubber tubes;
- separating funnel;
- ball cooler;
- drop catcher;
- glass parts (connected with rubber tubes).

Application of ammonia

Over the past few decades, the production of ammonia in the world market has been one of the leading places, amounting to approximately 100 million tons. It can be produced both in liquid form and in the form of ammonia water. Its scope is very extensive, but it mainly covers industry and medicine.

1. Industry:
- obtaining nitric acid for the production of artificial fertilizers;
- production of ammonium salts, urotropine, urea;
- for acid waste neutralization;
- use as a cheap refrigerant in the production of refrigerators;
- obtaining synthetic fibers (nylon, capron);
- when cleaning and dyeing wool, silk and cotton.

2. Medicine. Due to its irritant action, ammonia in the form of aqueous solution (ammonia) is widely distributed both in medical institutions and in everyday life: it irritates the mucous membranes of the upper respiratory tract, which helps to remove a person from fainting, stimulating his respiratory center. However, if inhaled, ammonia can cause severe watery eyes, coughing, loss of vision, skin redness and itching, eye pain, sometimes nerve damage, and pulmonary edema.

In surgical practice, the solution is used as a disinfectant. In addition, lotions with a solution of ammonia are used to neutralize toxins from insect and snake bites.

Precautionary measures

Ammonia is a toxic gas, a deadly poison for humans, therefore, its use requires special safety measures. When handling it, as with any other toxic gases, to protect the respiratory organs, mucous membranes of the eyes and skin, it is necessary to use a respirator, nitrile gloves, goggles, a gown, and other rubber products to protect the skin.

A high-quality apparatus for ammonia can be bought at the specialized online store of chemical reagents Moscow retail "Prime Chemicals Group". Ammonia, laboratory glassware, a magnetic stirrer and electronic laboratory scales for working with it are always available.

You can also buy a wide range of instruments, apparatus, chemicals, equipment and laboratory glassware in Moscow on our website. All goods are certified and comply with GOST standards.

"Prime Chemicals Group" - cooperate with us reliably and profitably!

physical properties.

Under normal pressure, ammonia liquefies at -33°C and solidifies at -78°C. The heat of fusion of NH 3 is 6 kJ/mol. The critical temperature of ammonia is 132 °C, the critical pressure is 112 atm. Cylinders containing it must be painted in yellow and have a black inscription "Ammonia".

Ammonia is a colorless gas with a characteristic pungent odor ("ammonia"). Its solubility in water is greater than that of all other gases: one volume of water absorbs about 1200 volumes of NH 3 at 0 ° C, and about 700 volumes of NH 3 at 20 ° C. Sales concentrated solution usually has a density of 0.91 g/cm 3 and contains 25 wt.% NH 3 (ie close to the composition of NH 3 ·3H 2 O).

The association of liquid ammonia is associated with its high heat of vaporization (23.4 kJ/mol). Since the critical temperature of ammonia is high (+132 °C) and a lot of heat is taken from the environment during its evaporation, liquid ammonia can serve as a working substance of refrigeration machines. r by air = M NH 3 / M medium air = 17 / 29 = 0.5862

Liquid ammonia is a good solvent for very a large number organic compounds, as well as many inorganic ones. For example, elemental sulfur dissolves well in liquid ammonia, strong solutions of which are red [and below +18 ° C contain a solvate S (NH 3) 2]. Of the salts, the derivatives of ammonium and alkali metals are more soluble than others, and the solubility of salts increases along the Cl-Br-I series. Examples are the following data (g / 100 g NH 3 at 25 ° C):

A similar course of change in the solubility of halides is also characteristic of a number of other cations. Many nitrates (and KMnO 4) are also highly soluble in liquid ammonia. In contrast, oxides, fluorides, sulfates and carbonates are generally insoluble in it.

Using the difference in the solubility of salts in liquid NH 3 and water, it is sometimes possible to reverse the commonly observed ion exchange reactions. For example, the balance according to the scheme:

2 AgNO 3 + BaBr 2 N 2 AgBr + Ba(NO 3) 2

AT aquatic environment almost completely shifted to the right (due to the insolubility of AgBr), and in an ammonia environment - to the left (due to the insolubility of BaBr 2).

A characteristic property of ammonia as an ionizing solvent is its pronounced leveling effect on the dissociation of various electrolytes. For example, HClO 4 and HCN, which are incommensurable with each other in terms of dissociation in an aqueous medium, in liquid ammonia are characterized by almost the same dissociation constants (5·10 -3 and 2·10 -3). Salts behave in liquid ammonia as electrolytes of medium strength or weak (for example, K = 2 10 -3 for KBr). Chlorides are usually somewhat less dissociated, and iodides somewhat more, of the corresponding bromides.

A feature of liquid ammonia is its ability to dissolve the most active metals, and the latter undergo ionization. For example, a dilute solution of sodium metal has blue color, conducts electric current like electrolyte solutions and contains Na + cations (solvated by ammonia) and anions (NH 3) x - . central part of such a complex anion is a free electron, which is in polarization interaction with environment(polaron). At higher concentrations of Na, its solution takes on the form of bronze and exhibits metallic electrical conductivity, i.e., along with solvated ammonia, it also contains free electrons. Below -42°C, the blue and bronze phases are able to coexist without mixing. Long term storage solutions of sodium in liquid ammonia is accompanied by their discoloration as a result of a very slow reaction according to the scheme:

2 Na + 2 NH 3 = 2 NaNH 2 + H 2­ .

With cesium (solubility 25 moles per 1000 g NH 3 at -50 ° C), a similar reaction takes place in a few minutes.

The metal dissolved in ammonia tends to split off valence electrons, which makes it possible to carry out peculiar displacement reactions. For example, using the solubility of KCl in liquid ammonia and the insolubility of CaCl 2, potassium can be isolated by calcium according to the scheme:

2 KCl + Ca ® CaCl 2 + 2 K.

There is an interesting indication that impregnation with liquid ammonia greatly increases the plasticity of wood. This makes it relatively easy to give it certain specified forms, which are preserved after removal of ammonia.

The dissolution of ammonia in water is accompanied by the release of heat (about 33 kJ/mol). The effect of temperature on solubility is illustrated by the data below, showing the number of parts by weight of NH 3 absorbed by one part by weight of water (at atmospheric pressure of ammonia):

Under normal conditions, approximately 3 N ammonia solution has the maximum electrical conductivity. Its solubility in organic solvents is much less than in water.

Chemical properties.

The formation of a covalent bond by the donor-acceptor mechanism.

1. Ammonia is a Lewis base. Its solution in water (ammonia water, ammonia) has an alkaline reaction (litmus - blue; phenolphthalein - raspberry) due to the formation of ammonium hydroxide.

NH 3 + H 2 O<-->NH4OH<-->NH 4 + + OH -

2. Ammonia reacts with acids to form ammonium salts.

NH 3 + HCl ® NH 4 Cl
2NH 3 + H 2 SO 4 ® (NH 4) 2 SO 4
NH 3 + H 2 O + CO 2® NH 4 HCO 3

Ammonia - reducing agent (oxidized to N 2 +1 O or N +2 O)

1. Decomposition when heated

2N -3 H 3 - t ° ® N 2 0 + 3H 2

2. Combustion in oxygen

a) without catalyst

4N -3 H 3 + 3O 2 ® 2N 2 0 + 6H 2 O

b) catalytic oxidation (kat = Pt)

4N -3 H 3 + 5O 2 ® 4N +2 O + 6H 2 O

3. Recovery of oxides of some metals

3Cu +2 O + 2N -3 H 3 ® 3Cu0 + N 2 0 + 3H 2 O

When a stream of ammonia is passed over heated CuO, it is oxidized to free nitrogen. The oxidation of ammonia with ozone leads to the formation of NH 4 NO 3 . It is interesting that, apparently, ordinary oxygen mixed with ozone also takes some part in this oxidation.

Ammonia is a good jet fuel. Like water, liquid ammonia is highly associated, mainly through the formation of H-bonds. However, they are relatively weak (about 4.2 kJ/mol). The viscosity of liquid ammonia is almost seven times less than the viscosity of water. Its density (0.68 and 0.61 g / cm 3, respectively, at -33 and +20 ° C) is also significantly less than that of water. Electricity liquid ammonia practically does not conduct, since electrolytic dissociation according to the scheme:

NH 3 + NH 3 S NH 4 + + NH 2 -

Negligibly small: ionic product = 2 10 -33 (at -50 °C).

Above 0 °C (under pressure), liquid ammonia mixes with water in any ratio. On strong solutions of water in ammonia at 30 °C, it was shown that its ionization is low. So, for a 9 M solution we have / = 1·10 -11.

For chemical characterization ammonia reactions are of primary importance three types: addition, hydrogen substitution and oxidation.

The most typical addition reactions for ammonia. In particular, under its action on many salts, crystalline ammoniates of the composition CaCl 2 ·8NH 3 , CuSO 4 ·4NH 3 , etc. are easily formed, similar to crystalline hydrates in the nature of formation and stability.

When ammonia dissolves in water, a partial formation of ammonium hydroxide occurs:

NH 3 + H 2 O s NH 4 OH

In this compound, the ammonium radical (NH 4) plays the role of a monovalent metal. Therefore, the electrolytic dissociation of NH 4 OH proceeds according to the main type:

NH 4 OH S NH 4 + OH "

Combining both of these equations, we get general idea about the equilibria that take place in an aqueous solution of ammonia:

NH 3 + H 2 O s NH 4 OH s NH 4 + OH "

Because of these equilibria, aqueous ammonia (often referred to simply as "ammonia") has a pungent odor. Due to the fact that the concentration of OH "ions" in the solution is low, NH 4 OH is considered as a weak base. Ammonium hydroxide is one of the most important chemical reagents, dilute solutions of which ("ammonia") are also used in medicine and household (when washing clothes and removing spots).

Analysis of data on the distribution of NH 3 between water and organic liquids shows that more than 90% of all ammonia dissolved in water is in the hydrated form. For the vapor phase above the water-ammonia solution, the presence of equilibrium was established according to the scheme:

2 NH 3 + H 2 O s 2 NH 3 H 2 O + 75 kJ,

Characterized by the value K = 1 10 -4 at 20 °C.

Atom, molecule.

The NH 3 molecule has the structure of a triangular pyramid with a nitrogen atom at the top. R HNH = 107.3°. Electrons H-N bonds quite strongly shifted from hydrogen to nitrogen, so the ammonia molecule as a whole is characterized by significant polarity.

The pyramidal structure of ammonia is energetically more favorable than the flat one by 25 kJ/mol. The molecule is polar; the N-H bond is characterized by an energy of 389 kJ/mol, but for the energies of successive dissociation of hydrogen atoms, values ​​of 435, 397 and 339 kJ/mol are given. Ammonia molecules are linked by weak hydrogen bonds:

An interesting property of ammonia molecules is their ability to undergo structural inversion, i.e. to "turning inside out" by passing the nitrogen atom through the plane of the base of the pyramid formed by hydrogen atoms. The potential barrier of this inversion is 25 kJ/mol, and only molecules rich enough in energy can carry it out. The inversion rate is relatively low - it is 1000 times less than the rate of orientation of NH 3 molecules by an electric field.

Receipt.

The conversion of free air nitrogen into a bound state is carried out mainly by the synthesis of ammonia:

N 2 + 3 H 2 S 2 NH 3 + 92 kJ.

The principle of equilibrium shift shows that the most favorable conditions for the formation of ammonia are perhaps more low temperature and possibly more high pressure. However, even at 700°C, the reaction rate is so slow (and hence the equilibrium is established so slowly) that there can be no question of its practical use. On the contrary, with more high temperatures, when the equilibrium state is established quickly, the ammonia content in the system becomes negligible. Thus, the technical implementation of the process under consideration turns out to be impossible, since, by accelerating the achievement of equilibrium by means of heating, we simultaneously shift its position in an unfavorable direction.

There is, however, a means to hasten the achievement of an equilibrium state without simultaneously shifting the equilibrium. Such often helpful means is a suitable catalyst. A suitable catalyst is metallic iron (with impurities of Al 2 O 3 and K 2 O). The process is usually carried out at a temperature of 400-600 °C (on a catalyst) and pressures of 100-1000 atm. After separation of ammonia from the gas mixture, the latter is again introduced into the cycle.

In the process of searching for a catalyst for the synthesis of ammonia, about 20 thousand different substances were tried. A widely used iron catalyst is usually prepared by heating a close mixture of FeO and Fe 2 O 3 (containing small impurities of Fe, Al 2 O 3 and KOH) in an atmosphere of composition 3H 2 +N 2 . Since H 2 S, CO, CO 2 , water vapor and oxygen quickly "poison" the catalyst, the nitric-hydrogen mixture supplied to it must be carefully freed from them. With the right technological regime, the catalyst operates smoothly for several years.

For further development In the synthetic ammonia industry, it may turn out to be significant that at pressures of 2000 atm and above, the synthesis of ammonia from a nitric-hydrogen mixture proceeds well even without a special catalyst. The practical yield of ammonia at 850°C and 4500 atm is 97%. Of particular importance is the fact that at ultrahigh pressures, the presence of various impurities in the source gases does not affect the course of the process.

The synthesis of ammonia was practically realized in 1913, when 7 tons of NH 3 were obtained in this way. At present, this synthesis is the main industrial method for obtaining bound nitrogen with an annual world output of tens of millions of tons.

In addition to the direct synthesis of ammonia from the elements, some industrial value for the binding of nitrogen in the air has been developed in 1905. cyanamide method. The latter is based on the fact that at 1000 °C calcium carbide (obtained by calcining a mixture of lime and coal in an electric furnace) reacts with free nitrogen according to the equation:

CaC 2 + N 2 = CaCN 2 + C + 293 kJ.

The calcium cyanamide obtained in this way (Ca=N-Cє N) is a gray (from carbon impurity) powder. Under the action of superheated (i.e., heated above 100 ° C) water vapor, it decomposes with the release of ammonia:

CaCN 2 + 3 H 2 O \u003d CaCO 3 + 2 NH 3 + 222 kJ.

The decomposition of calcium cyanamide with water proceeds slowly at ordinary temperatures. Therefore, it can be used as a nitrogen fertilizer, introducing it into the soil long before sowing. The presence of calcium makes it particularly suitable for podzolic soils. "Cyanamide plays the role of not only nitrogenous, but also lime fertilizer, and lime is free application to nitrogen" (D.N. Pryanishnikov).

Under laboratory conditions, NH 3 is obtained by treating solid NH 4 Cl with a saturated KOH solution. The released gas can be dried by passing through a vessel with solid KOH or with freshly calcined calcium oxide (CaO). H 2 SO 4 and CaCl 2 cannot be used for drying, since ammonia forms compounds with them.

2NH 4 Cl + Ca (OH) 2 - t ° ® CaCl 2 + 2NH 3 + 2H 2 O

(NH 4) 2 SO 4 + 2KOH - t ° ® K 2 SO 4 + 2NH 3 + 2H 2 O

Ammonia can only be collected according to method (A), because it is lighter than air and very soluble in water.

Action on the body.

Ammonia strongly irritates the mucous membranes already at 0.5% of its content in the air. Acute ammonia poisoning causes damage to the eyes and respiratory tract, shortness of breath and pneumonia. First aid means are fresh air, plenty of eyewash with water, inhalation of water vapor. Chronic ammonia poisoning causes indigestion, catarrh of the upper respiratory tract and hearing loss. The maximum permissible concentration of NH 3 in the air of industrial premises is 0.02 mg/l. Ammonia-air mixtures containing from 16 to 28 vol.% ammonia are explosive.

Application.

Because Since the decomposition of calcium cyanamide with water proceeds slowly at ordinary temperatures, it can be used as a nitrogen fertilizer, introducing it into the soil long before sowing. The presence of calcium makes it particularly suitable for podzolic soils. "Cyanamide plays the role of not only nitrogenous, but also lime fertilizer, and lime is a free addition to nitrogen" (D.N. Pryanishnikov).

Commercially available ammonia usually contains about 10% ammonia. He finds and medical application. In particular, inhalation of its vapors or ingestion (3-10 drops per glass of water) is used to relieve the state of severe intoxication. Lubricating the skin with ammonia reduces the effect of insect bites. Very dilute ammonia is convenient for wiping windows and washing floors painted with oil paint, stronger - to remove traces of flies, clean silver or nickel-plated objects.

When removing stains good results give in many cases the following compositions (by volume): a) 4 parts of ammonia, 5 parts of ether and 7 parts of wine alcohol (denatured alcohol); b) 5 parts of ammonia, 2 parts of gasoline and 10 parts of wine alcohol; c) 10 parts of ammonia, 7 parts of wine alcohol, 3 parts of chloroform and 80 parts of gasoline; d) 5 parts of ammonia, 3 parts of acetone and 20 parts of an alcohol solution of soap.

Got on clothes oil paint it is recommended to rub with pieces of cotton wool, first moistened with turpentine, and then with ammonia. To remove an ink stain, it is usually sufficient to treat it with ammonia and rinse with water.