Hydrochloric (Hydrochloric) acid - very strong, dangerous Chemical substance, which has quite wide application in many areas of human life.
Brine is hydrogen chloride (HCL, an odorless thermal gas) combined with water (H2O). The boiling point depends on the concentration of the solution. The substance is flammable, storage conditions: only in dry rooms.
Used in medicine, dentistry, and for teeth whitening. If the stomach secretes insufficient amount of juice (enzyme), salt - acid solution used as aid. In chemical laboratories, chlorine is a popular reagent for biochemistry experiments, sanitary standards and diagnostics.
Hydrochloric acid has become widely known in industry: dyeing fabrics, leather, soldering metal, removing scale, oxides, and is included in the manufacture of pharmaceuticals, as an oxidizing agent, etc.
Chemical Spectrum Properties
Acid interacts with many metals and salts. It is considered quite strong and is on par with chamois. The main reaction manifests itself to all groups of metals located to the left of hydrogen (magnesium, iron, zinc - electrical potentials).
As a result of such exposure, salts are formed with the release of H into the air.
A diluted hydrochloric solution reacts with salts, but only with those formed by less strong acids. The well-known sodium and calcium carbonate, after interacting with it, disintegrate into water and carbon monoxide.
Nitric acid– qualitative response to saline solution. To obtain it, it is necessary to add silver nitrate to this reagent, as a result, a precipitate will form white, from which nitrogen substance is obtained
Many interesting experiments are carried out using this mixture of water and hydrogen. For example, they dilute it with ammonia. As a result, you will get white smoke, thick, with the consistency of small crystals. Methylamine, aniline, manganese dioxide, potassium carbonate are reagents that are also susceptible to the influence of acid.
How is hydrochloric acid produced in the laboratory?
The production of the substance is large-scale, sale is free. In conditions laboratory experiments The solution is extracted by the action of high concentration sulfuric acid on ordinary kitchen salt (sodium chloride).
There are 2 methods for dissolving hydrogen chloride in water:
- Hydrogen is burned in chlorine (synthetic).
- Associated (absorbed). Its essence is to carry out organic chlorination, dehydrochlorination.
Chemical properties of hydrochloric acid quite high.
The substance is easily synthesized by pyrolysis of organochlorine waste. This happens as a result of the breakdown of hydrocarbons with a complete lack of oxygen. You can also use metal chlorides, which are raw materials inorganic substances. If there is no concentrated sulfuric acid (electrolyte), take diluted one.
Potassium permanganate is another way to make a salt solution.
As for obtaining the reagent in natural conditions, most often this chemical mixture can be found in the waters of volcanic waste. Hydrogen chloride is a component of the minerals sylvite (potassium chloride, similar in appearance to game dice), bischofite. All these are methods of extracting the substance in industry.
In the human body, this enzyme is found in the stomach. A solution can be either an acid or a base. One of the common extraction methods is called sulfate.
How and why they are used
Perhaps this is rightfully one of the important substances that is found and necessary in almost all sectors of human life.
Localization of application:
- Metallurgy. Cleaning surfaces from oxidized areas, dissolving rust, processing before soldering, tinning. Hydrochloric acid helps to extract small inclusions of metals from ores. Zirconium and titanium are obtained using a method of converting oxides into chlorides.
- Food technology industry. A low concentration solution is used as a food additive. Gelatin and fructose for diabetics contain a pure emulsifier. Regular soda also has a high content of this substance. On the product packaging you will see it called E507.
- Field of medicine. If the indicator is insufficient acidic environment in stomach and intestinal problems. Low level Ph leads to cancer. Even with proper nutrition and plenty of vitamins, the danger does not disappear; tests must be carried out to obtain juice from gastric tract, because in an insufficiently acidic environment useful material are practically not absorbed, digestion is disrupted.
- The salt solution is used as an inhibitor - protection against dirt and infections, antiseptic effect. For the production of adhesive mixtures and ceramic products. Heat exchangers are washed with it.
- The procedure for purifying drinking water is also not complete without the participation of chlorine.
- Production of rubber, bleaching of fabric bases.
- You can care for your lenses using this solution.
- Mouth rinse at home
- The substance conducts electricity well.
Instructions for use
Hydrochloric acid can be used internally in medicine only as prescribed by a doctor. You cannot self-medicate.
The instructions are simple: The usual way to prepare a solution as a drug is to stir before use until it completely disappears in water. For half a 200 gram glass, 15 drops of medicine are prescribed. Take only during meals, 4 times a day.
Do not overdo it, this is not a panacea for diseases, consultation with a specialist is important. In case of overdose, ulcerative formations occur on the mucous membrane of the esophagus.
Side effects and contraindications
Refrain from taking if you are in a mood to allergic reactions, this may have a bad effect on general functions body.
Severe poisoning and burns
If the product comes into contact with the skin in concentrated form, you can get a severe toxicological burn. Penetration of excess steam into Airways(larynx, throat) helps cause poisoning.
A severe suffocating cough appears, and the sputum may contain blood. Vision becomes cloudy, you want to constantly rub your eyes, the mucous membranes are irritated. The iris does not respond to bright light.
Getting burned by hydrochloric acid is not as scary as sulfuric acid, but the vapors that can enter the gastrointestinal tract can lead to serious consequences of alkali intoxication.
The first sign (symptom) is the presence elevated temperature bodies. The characteristics of the action of this substance on the esophagus are visible in the following: wheezing in the lungs, vomiting, physical weakness, inability to take a deep breath, swelling of the respiratory tract.
When hit large quantity Inside, the toxicological picture is terrible: the volume of vomit increases, facial cyanosis and arrhythmia develop. Rib cage is compressed (asphyxia), followed by swelling of the larynx and death from painful shock.
For the listed symptoms, there is a certain classification of first aid actions.
It is very important to distinguish the stages of intoxication:
- If a person is poisoned by vapors, it is necessary to immediately take him out into clean air. Wash your throat with sodium bicarbonate solution and apply a compress to your eyes. Go to the hospital immediately.
- If the action of the acid is directed towards skin covering child or adult, it is important to properly treat the burned area. Rinse the skin for 15 minutes and apply burn ointment.
- If damage is caused by the solution internal organs, urgent cleansing of the stomach by intubation and hospitalization is necessary.
Analogues of hydrochloric acid in preparations
Since the permissible amount of the substance is used in medicine, it is contained in the following medications:
- Magnesium Sulfate.
- Calcium chloride.
- Reamberin.
Remember that for human consumption, hydrogen chloride acid is used only in diluted form.
To prepare the solution, it is necessary to mix the calculated amounts of acid of known concentration and distilled water.
Example.
It is necessary to prepare 1 liter of HCL solution with a concentration of 6% wt. from hydrochloric acid with a concentration of 36% wt.(this solution is used in KM carbonatometers produced by NPP Geosphere LLC)
.
By table 2Determine the molar concentration of an acid with a weight fraction of 6% wt. (1.692 mol/l) and 36% wt. (11.643 mol/l).
Calculate the volume of concentrated acid containing the same amount of HCl (1.692 g-eq.) as in the prepared solution:
1.692 / 11.643 = 0.1453 l.
Therefore, adding 145 ml of acid (36% wt.) to 853 ml of distilled water will obtain a solution of the given weight concentration.
Experiment 5. Preparation of aqueous solutions of hydrochloric acid of a given molar concentration.
To prepare a solution with the required molar concentration (Mp), it is necessary to pour one volume of concentrated acid (V) into the volume (Vв) of distilled water, calculated according to the ratioVв = V(M/Mp – 1)
where M is the molar concentration of the starting acid.
If the acid concentration is not known, determine it by density usingtable 2.
Example.
The weight concentration of the acid used is 36.3% wt. It is necessary to prepare 1 liter of an aqueous solution of HCL with a molar concentration of 2.35 mol/l.
By table 1find by interpolating the values of 12.011 mol/l and 11.643 mol/l the molar concentration of the acid used:
11.643 + (12.011 – 11.643)·(36.3 – 36.0) = 11.753 mol/l
Using the above formula, calculate the volume of water:
Vв = V (11.753 / 2.35 – 1) = 4 V
Taking Vв + V = 1 l, obtain the volume values: Vв = 0.2 l and V = 0.8 l.
Therefore, to prepare a solution with a molar concentration of 2.35 mol/L, you need to pour 200 ml of HCL (36.3% wt.) into 800 ml of distilled water.
Questions and tasks:
What is the concentration of a solution?
What is the normality of a solution?
How many grams of sulfuric acid are contained in the solution if 20 ml are used for neutralization? sodium hydroxide solution whose titer is 0.004614?
Materials and equipment:
Progress:
Iodometric method
Reagents:
1. Potassium iodide is chemically pure, crystalline, and does not contain free iodine.
Examination. Take 0.5 g of potassium iodide, dissolve in 10 ml of distilled water, add 6 ml of buffer mixture and 1 ml of 0.5% starch solution. The reagent should not turn blue.
2. Buffer mixture: pH = 4.6. Mix 102 ml of a molar solution of acetic acid (60 g of 100% acid in 1 liter of water) and 98 ml of a molar solution of sodium acetate (136.1 g of crystalline salt in 1 liter of water) and bring to 1 liter with distilled water, previously boiled.
3. 0.01 N sodium hyposulfite solution.
4. 0.5% starch solution.
5. 0.01 N solution of potassium dichromate. Setting the titer of a 0.01 N hyposulfite solution is carried out as follows: pour 0.5 g of pure potassium iodide into a flask, dissolve it in 2 ml of water, add first 5 ml of hydrochloric acid (1:5), then 10 ml of 0.01 N dichromate solution potassium and 50 ml of distilled water. The released iodine is titrated with sodium hyposulfite in the presence of 1 ml of starch solution, added at the end of the titration. The correction factor to the sodium hyposulfite titer is calculated using the following formula: K = 10/a, where a is the number of milliliters of sodium hyposulfite used for titration.
Analysis progress:
a) add 0.5 g of potassium iodide into a conical flask;
b) add 2 ml of distilled water;
c) stir the contents of the flask until the potassium iodide dissolves;
d) add 10 ml of buffer solution if the alkalinity of the water being tested is not higher than 7 mg/eq. If the alkalinity of the test water is higher than 7 mg/eq, then the number of milliliters of the buffer solution should be 1.5 times greater than the alkalinity of the test water;
e) add 100 ml of test water;
f) titrate with hyposulfite until the solution turns pale yellow;
g) add 1 ml of starch;
h) titrate with hyposulfite until the blue color disappears.
X = 3.55 N K
where H is the number of ml of hyposulfite spent on titration,
K - correction factor to the titer of sodium hyposulfite.
Questions and tasks:
What is the iodometric method?
What is pH?
LPZ No. 6: Determination of chloride ion
Goal of the work:
Materials and equipment: drinking water, litmus paper, ash-free filter, potassium chromate, silver nitrate, titrated sodium chloride solution,
Progress:
Depending on the results of the qualitative determination, 100 cm 3 of the test water or a smaller volume (10-50 cm 3) is selected and adjusted to 100 cm 3 with distilled water. Chlorides are determined at concentrations up to 100 mg/dm 3 without dilution. The pH of the titrated sample should be in the range of 6-10. If the water is cloudy, it is filtered through an ashless filter, washed hot water. If the water has a color value above 30°, the sample is decolorized by adding aluminum hydroxide. To do this, add 6 cm3 of aluminum hydroxide suspension to 200 cm 3 of sample, and the mixture is shaken until the liquid becomes discolored. The sample is then filtered through an ashless filter. The first portions of the filtrate are discarded. A measured volume of water is added to two conical flasks and 1 cm 3 of potassium chromate solution is added. One sample is titrated with a solution of silver nitrate until a faint orange tint appears, the second sample is used as a control sample. If the chloride content is significant, a precipitate of AgCl is formed, which interferes with the determination. In this case, add 2-3 drops of titrated solution to the titrated first sample. NaCl solution until the orange tint disappears, then titrate the second sample, using the first as a control sample.
The following interfere with the determination: orthophosphates in concentrations exceeding 25 mg/dm 3 ; iron in a concentration of more than 10 mg/dm3. Bromides and iodides are determined in concentrations equivalent to Cl - . When normally present in tap water, they do not interfere with determination.
2.5. Processing the results.
where v is the amount of silver nitrate spent on titration, cm 3;
K is the correction factor to the titer of the silver nitrate solution;
g is the amount of chlorine ion corresponding to 1 cm 3 solution of silver nitrate, mg;
V is the sample volume taken for determination, cm3.
Questions and tasks:
Methods for determining chloride ions?
Conductometric method for determining chloride ions?
Argentometry.
Goal of the work:
Materials and equipment:
Experiment 1. Determination of the total hardness of tap water
Measure 50 ml of tap water with a measuring cylinder and pour it into a 250 ml flask, add 5 ml of ammonia buffer solution and an indicator - eriochrome black T - until a pink color appears (a few drops or a few crystals). Fill the burette with 0.04 N EDTA solution (synonyms: Trilon B, Complexon III) to the zero mark.
Titrate the prepared sample slowly with constant stirring with a solution of complexone III until the pink color changes to blue. Record the titration result. Repeat the titration one more time.
If the difference in titration results exceeds 0.1 ml, then titrate the water sample a third time. Determine the average volume of complexone III (V K, CP) consumed for titration of water, and from it calculate the total hardness of the water.
F TOTAL = , (20) where V 1 – volume of analyzed water, ml; V K,SR – average volume of complexone III solution, ml; N K – normal concentration of complexone III solution, mol/l; 1000 – conversion factor mol/l to mmol/l.
Write the results of the experiment in the table:
| V K,SR | N K | V 1 | F GEN |
Example 1. Calculate the hardness of water, knowing that 500 liters contain 202.5 g of Ca(HCO 3) 2.
Solution. 1 liter of water contains 202.5:500 = 0.405 g Ca(HCO 3) 2. The equivalent mass of Ca(HCO 3) 2 is 162:2 = 81 g/mol. Therefore, 0.405 g is 0.405:81 = 0.005 equivalent masses or 5 mmol eq/L.
Example 2. How many grams of CaSO 4 are contained in one cubic meter of water if the hardness due to the presence of this salt is 4 mmol eq
CONTROL QUESTIONS
1. What cations are called hardness ions?
2. What technological indicator of water quality is called hardness?
3. Why can’t hard water be used for steam recovery in thermal and nuclear power plants?
4. Which softening method is called thermal? Which chemical reactions occur when softening water using this method?
5. How is water softened using the sedimentation method? What reagents are used? What reactions take place?
6. Is it possible to soften water using ion exchange?
LPZ No. 8 “Photocolorimetric determination of element content in solution”
Purpose of the work: to study the design and operating principle of the KFK-2 photocolorimeter
PHOTOELECTROCOLORIMETERS. A photoelectric colorimeter is an optical device in which monochromatization of the radiation flux is carried out using light filters. Photoelectric concentration colorimeter KFK – 2.
Purpose and technical data. Single-beam photocolorimeter KFK - 2
designed for measuring transmittance, optical density and concentration of colored solutions, scattering suspensions, emulsions and colloidal solutions in the spectral region of 315–980 nm. The entire spectral range is divided into spectral intervals, separated using light filters. Transmission measurement limits from 100 to 5% (optical density from 0 to 1.3). Main absolute error transmittance measurements no more than 1%. Rice. General form KFK-2. 1 - illuminator; 2 - handle for inserting color filters; 3 - cuvette compartment; 4 - handle for moving cuvettes; 5 - handle (introducing photodetectors into the light flux) “Sensitivity”; 6 - handle for setting the device to 100% transmission; 7 - microammeter. Light filters. In order to isolate rays of certain wavelengths from the entire visible region of the spectrum, selective light absorbers - light filters - are installed in photocolorimeters on the path of light fluxes in front of the absorbing solutions. Operating procedure
1. Turn on the colorimeter 15 minutes before starting measurements. During heating, the cuvette compartment must be open (in this case, the curtain in front of the photodetector blocks the light beam).
2. Enter a working filter.
3. Set the colorimeter sensitivity to minimum. To do this, set the “SENSITIVITY” knob to position “1”, the “SETTING 100 ROUGH” knob to the extreme left position.
4. Set the colorimeter needle to zero using the “ZERO” potentiometer.
5. Place the cuvette with the control solution into the light beam.
6. Close the cuvette compartment lid
7. Using the “SENSITIVITY” and “SETTING 100 ROUGH” and “FINE” knobs, set the microammeter needle to the “100” division of the transmittance scale.
8. By turning the handle of the cuvette chamber, place the cuvette with the test solution into the light stream.
9. Take readings on the colorimeter scale in the appropriate units (T% or D).
10. After finishing work, unplug the colorimeter, clean and wipe dry the cuvette chamber. Determination of the concentration of a substance in a solution using KFK-2. When determining the concentration of a substance in a solution using a calibration graph, the following sequence should be observed:
examine three samples of potassium permanganate solution of different concentrations and record the results in a journal.
Questions and tasks:
Design and principle of operation of KFK - 2
Basic literature for students:
1. Course of basic notes according to the program OP.06 Fundamentals of Analytical Chemistry.-Manual / A.G. Bekmukhamedova - teacher of general professional disciplines ASHT - Branch of the Federal State Budgetary Educational Institution of Higher Professional Education OGAU; 2014
Additional literature for students:
1. Klyukvina E.Yu. Basics of general and inorganic chemistry: tutorial/ E.Yu. Klyukvina, S.G. Bezryadin. - 2nd ed. - Orenburg. Publishing center OSAU, 2011 - 508 pages.
Basic literature for teachers:
1. 1.Klyukvina E.Yu. Fundamentals of general and inorganic chemistry: textbook / E.Yu. Klyukvina, S.G. Bezryadin. - 2nd ed. - Orenburg. Publishing center OSAU, 2011 - 508 pages.
2. Klyukvina E.Yu. Laboratory notebook on analytical chemistry. - Orenburg: OSAU Publishing Center, 2012 - 68 pages
Additional reading for teachers:
1. 1.Klyukvina E.Yu. Fundamentals of general and inorganic chemistry: textbook / E.Yu. Klyukvina, S.G. Bezryadin. - 2nd ed. - Orenburg. Publishing center OSAU, 2011 - 508 pages.
2. Klyukvina E.Yu. Laboratory notebook on analytical chemistry. - Orenburg: OSAU Publishing Center, 2012 - 68 pages
Hydrochloric acid is one of the most powerful and dangerous substances for humans on the list of hazardous substances. However, what is surprising is that it exists in the body of every person: hydrochloric acid is an integral part gastric juice and plays an important role in digestive processes. In an amount of 0.2%, it promotes the transition of food masses from the stomach to duodenum and neutralizes microbes entering the stomach from external environment. It also activates the enzyme pepsinogen, participates in the formation of secretin and some other hormones that stimulate the activity of the pancreas. For this purpose, it is used in medicine, prescribing its solution to patients to increase the acidity of gastric juice. In general, hydrochloric acid has wide applications in our lives. For example, in heavy industry - to produce chlorides various metals, in the textile industry - for the production of synthetic dyes; For Food Industry they make it from acetic acid, for pharmaceutical - Activated carbon. It is also a component of various adhesives and hydrolytic alcohol. It is used for etching metals, cleaning various vessels, casing pipes of boreholes from carbonates, oxides and other sediments and contaminants. In metallurgy, hydrochloric acid is used to treat ores, and in the leather industry, leather is used before tanning and dyeing. Hydrochloric acid is transported in glass bottles or rubberized (rubber-coated) metal vessels, as well as in plastic containers.
What is it as a chemical?
Hydrochloric acid, or hydrochloric acid, is an aqueous solution of hydrogen chloride HCl, which is a clear, colorless liquid with a pungent odor of hydrogen chloride. The technical variety of acid has a yellowish-green color due to impurities of chlorine and iron salts. The maximum concentration of hydrochloric acid is about 36% HCl; such a solution has a density of 1.18 g/cm3. Concentrated acid“smoke” in air, since the released gaseous HCl forms tiny droplets of hydrochloric acid with water vapor.
Despite this characteristic, when in contact with air, hydrochloric acid is not flammable or explosive. But at the same time it is one of the most strong acids and dissolves (with the release of hydrogen and the formation of salts - chlorides) all metals in the voltage series up to hydrogen. Chlorides are also formed when hydrochloric acid reacts with metal oxides and hydroxides. WITH strong oxidizing agents it behaves like a reducer.
Salts of hydrochloric acid are chlorides and, with the exception of AgCl, Hg2Cl2, are highly soluble in water. Materials such as glass, ceramics, porcelain, graphite, and fluoroplastic are resistant to hydrochloric acid.
Hydrochloric acid is obtained from hydrogen chloride in water, which, in turn, is either directly synthesized from hydrogen and chlorine, or obtained by the action of sulfuric acid on sodium chloride.
Industrially produced (technical) hydrochloric acid has a strength of at least 31% HCl (synthetic) and 27.5% HCl (from NaCI). A commercial acid is called concentrated if it contains 24% or more HCl; if the HCl content is less, then the acid is called dilute.
Hydrochloric acid (H Cl)hazard class 3
(concentrated hydrochloric acid)
Colorless, transparent, aggressive, non-flammable liquid with a pungent odor of hydrogen chloride. Represents 36% ( concentrated) a solution of hydrogen chloride in water. Heavier than water. It boils at a temperature of +108.6 0 C, and hardens at a temperature of –114.2 0 C. It dissolves well in water in all proportions, “smoke” in air due to the formation of hydrogen chloride with water vapor and fog droplets. Interacts with many metals, metal oxides and hydroxides, phosphates and silicates. When interacting with metals, it releases a flammable gas (hydrogen); when mixed with other acids, it causes spontaneous combustion of some materials. Destroys paper, wood, fabrics. Causes burns upon contact with skin. Exposure to hydrochloric acid fog, which is formed as a result of the interaction of hydrogen chloride with water vapor in the air, causes poisoning.
Hydrochloric acid is used in chemical synthesis, for processing ores, pickling metals. It is obtained by dissolving hydrogen chloride in water. Technical hydrochloric acid is produced with a strength of 27.5-38% by weight.
Hydrochloric acid is transported and stored in rubberized (coated with a layer of rubber) metal railway and automobile tanks, containers, cylinders, which are its temporary storage. Typically, hydrochloric acid is stored in above-ground cylindrical vertical rubberized tanks (volume 50-5000 m3) at atmospheric pressure and ambient temperature or in 20-liter glass bottles. Maximum storage volumes 370 tons.
Extremely permissible concentration(maximum concentration) in the air inhabited items is 0.2 mg/m 3 in the air of the working area of industrial premises 5 mg/m3. At a concentration of 15 mg/m3, the mucous membranes of the upper respiratory tract and eyes are affected, a sore throat, hoarseness, cough, runny nose, shortness of breath, and difficulty breathing appear. At concentrations of 50 mg/m3 and above, bubbling breathing occurs, sharp pains behind the sternum and in the stomach area, vomiting, spasm and swelling of the larynx, loss of consciousness. Concentrations of 50-75 mg/m 3 are difficult to tolerate. A concentration of 75-100 mg/m3 is intolerable. A concentration of 6400 mg/m 3 within 30 minutes is lethal. The maximum permissible concentration when using industrial and civil gas masks is 16,000 mg/m 3 .
When eliminating accidents, associated with a spill of hydrochloric acid, it is necessary to isolate the danger zone, remove people from it, stay to the windward side, and avoid low places. Directly at the accident site and in contamination zones with high concentrations at a distance of up to 50 m from the spill site, work is carried out in insulating gas masks IP-4M, IP-5 (for chemical bound oxygen) or breathing apparatus ASV-2, DASV (compressed air), KIP-8, KIP-9 (compressed oxygen) and skin protection products (L-1, OZK, KIKH-4, KIKH-5). At a distance of more than 50 m from the source, where the concentration sharply decreases, skin protective equipment need not be used, and for respiratory protection, industrial gas masks with boxes of brands B, BKF, as well as civilian gas masks GP-5, GP-7, PDF-2D are used , PDF-2Sh complete with an additional cartridge DPG-3 or respirators RPG-67, RU-60M with a box of brand V.
Means of protection |
Time protective action(hour) at concentrations (mg/m 3) |
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Name |
Brand boxes |
5000 |
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Industrial gas masks large size |
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BKF |
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Civilian gas masks GP-5, GP-7, PDF-2D, PDF-2SH |
with DPG-3 |
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Respirators RU-60M, RPG-67 |
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Due to the fact that hydrochloric acid "smoke" in the air with the formation droplets of fog interacting hydrogen chloride with water vapor, the presence in the air is determined hydrogen chloride.
The presence of hydrogen chloride is determined:
In the air of an industrial zone with an OKA-T-N gas analyzer Cl , gas alarm IGS-98-N Cl , universal gas analyzer UG-2 with a measurement range of 0-100 mg/m 3 , gas detector of industrial chemical emissions GPHV-2 in the range of 5-500 mg/m 3 .
In open space – with SIP “CORSAR-X” devices.
Indoors – SIP “VEGA-M”
Neutralizes hydrochloric acid and hydrogen chloride vapors the following alkaline solutions:
5% aqueous solution caustic soda (for example, 50 kg of caustic soda per 950 liters of water);
5% aqueous solution of soda powder (for example, 50 kg of soda some powder for 950 liters of water);
5% aqueous solution of slaked lime (for example, 50 kg of slaked lime per 950 liters of water);
5% water solution of caustic soda (for example, 50 kg of caustic soda per 950 liters of water);
In the event of a hydrochloric acid spill and the absence of an embankment or pan, the spill site is fenced off with an earthen rampart, hydrogen chloride vapor is precipitated by placing a water curtain (water consumption is not standardized), the spilled acid is neutralized to safe concentrations with water (8 tons of water per 1 ton of acid) in compliance with all measures precautions or a 5% aqueous solution of alkali (3.5 tons of solution per 1 ton of acid) and neutralize 5% aqueous solution of alkali (7.4 tons of solution per 1 ton of acid).
To spray water or solutions, watering and fire trucks, auto-filling stations (ATs, PM-130, ARS-14, ARS-15), as well as hydrants and special systems available at chemically hazardous facilities, are used.
To dispose of contaminated soil at the site of a hydrochloric acid spill, the surface layer of soil is cut off to the depth of contamination, collected and transported for disposal using earthmoving vehicles (bulldozers, scrapers, motor graders, dump trucks). The cut areas are covered with a fresh layer of soil and washed with water for control purposes.
Leader actions: isolate the danger zone within a radius of at least 50 meters, remove people from it, stay to the windward side, avoid low places. Enter the accident area only in full protective clothing.
Providing first aid:
In the contaminated area: rinse eyes and face generously with water, put on anti-vogaza, urgent withdrawal (removal) from the outbreak.
After evacuating a contaminated area: warming, rest, washing off the acid from open areas of skin and clothing with water, washing the eyes abundantly with water, if breathing is difficult, apply heat to the neck area, subcutaneously - 1 ml. 0.1% atropine sulfate solution. Immediate evacuation to a medical facility.
Structural formula
True, empirical, or gross formula: HCl
Chemical composition of hydrochloric acid
Molecular weight: 36.461
Hydrochloric acid(also hydrochloric acid, hydrochloric acid, hydrogen chloride) - a solution of hydrogen chloride (HCl) in water, a strong monobasic acid. Colorless, transparent, caustic liquid, “smoking” in air (technical hydrochloric acid is yellowish in color due to impurities of iron, chlorine, etc.). It is present in a concentration of about 0.5% in the human stomach. The maximum concentration at 20 °C is 38% by weight, the density of such a solution is 1.19 g/cm³. Molar mass 36.46 g/mol. Salts of hydrochloric acid are called chlorides.
Physical properties
The physical properties of hydrochloric acid strongly depend on the concentration of dissolved hydrogen chloride. When solidified, it gives crystal hydrates of the compositions HCl H 2 O, HCl 2H 2 O, HCl 3H 2 O, HCl 6H 2 O.
Chemical properties
- Interaction with metals in a row electrochemical potentials to hydrogen, forming a salt and releasing hydrogen gas.
- Interaction with metal oxides to form soluble salt and water.
- Interaction with metal hydroxides to form soluble salt and water (neutralization reaction).
- Interaction with metal salts formed by weaker acids, such as carbonic acid.
- Interaction with strong oxidizing agents (potassium permanganate, manganese dioxide) with the release of chlorine gas.
- Reaction with ammonia to form thick white smoke consisting of tiny crystals of ammonium chloride.
- A qualitative reaction to hydrochloric acid and its salts is its interaction with silver nitrate, which forms a cheesy precipitate of silver chloride, insoluble in nitric acid.
Receipt
Hydrochloric acid is prepared by dissolving hydrogen chloride gas in water. Hydrogen chloride is produced by burning hydrogen in chlorine; the acid obtained in this way is called synthetic. Hydrochloric acid is also obtained from exhaust gases - by-product gases formed during various processes, for example, during the chlorination of hydrocarbons. The hydrogen chloride contained in these gases is called free gas, and the acid thus obtained is called free gas. In recent decades, the share of gas-free hydrochloric acid in production volume has gradually increased, displacing acid produced by burning hydrogen in chlorine. But hydrochloric acid obtained by burning hydrogen in chlorine contains fewer impurities and is used when high purity is required. In laboratory conditions, a method developed by alchemists is used, which consists of the action of concentrated sulfuric acid on table salt. At temperatures above 550 °C and excess table salt interaction is possible. It is possible to obtain by hydrolysis of magnesium and aluminum chlorides (hydrated salt is heated). These reactions may not proceed to completion with the formation of basic chlorides (oxychlorides) of variable composition, for example. Hydrogen chloride is highly soluble in water. Thus, at 0 °C, 1 volume of water can absorb 507 volumes of HCl, which corresponds to an acid concentration of 45%. However, at room temperature the solubility of HCl is lower, so in practice 36% hydrochloric acid is usually used.
Application
Industry
- It is used in hydrometallurgy and electroplating (pickling, pickling), for cleaning the surface of metals during soldering and tinning, for producing chlorides of zinc, manganese, iron and other metals. In a mixture with surfactants, it is used to clean ceramic and metal products (inhibited acid is required here) from contamination and disinfection.
- Registered in the food industry as an acidity regulator ( food supplement E507). Used to make seltzer (soda) water.
Medicine
- A natural constituent of human gastric juice. In a concentration of 0.3-0.5%, usually mixed with the enzyme pepsin, it is administered orally in case of insufficient acidity.
Features of treatment
Highly concentrated hydrochloric acid is a caustic substance that causes severe chemical burns. Contact with eyes is especially dangerous. To neutralize burns, use a weak alkali solution, usually baking soda. When opening vessels with concentrated hydrochloric acid, hydrogen chloride vapors, attracting air moisture, form a fog that irritates the eyes and respiratory tract of humans. Reacting with strong oxidizing agents (bleach, manganese dioxide, potassium permanganate) forms toxic chlorine gas. In the Russian Federation, the circulation of hydrochloric acid with a concentration of 15% or more is limited.
