Acids: examples, table. Properties of acids
Acids are such chemical compounds,which are capable of giving off an electrically charged ion (cation) of hydrogen, and also accept two interacting electrons, resulting in a covalent bond.
In this article we will look at the basic acids that are studied in secondary schools of general education schools, as well as learn many interesting facts about a variety of acids. Let's get started.
Acids: Species
In chemistry, there are many differentacids, which have very different properties. Chemists distinguish between acids in content in oxygen, in volatility, in solubility in water, in strength, in stability, in an organic or inorganic class of chemical compounds. In this article, we will consider a table in which the most known acids are presented. The table will help remember the name of the acid and its chemical formula.
| Chemical formula | Name of acid |
| H2S | Hydrogen sulfide |
| H2SO4 | Sernaya |
| HNO3 | Nitrogen |
| HNO2 | Nitrogen |
| HF | Plavikovaya |
| HCl | Salt |
| H3PO4 | Phosphoric |
| H2CO3 | Coal |
So, everything is clearly visible. In this table, the most well-known in the chemical industry acids are presented. The table will help to memorize names and formulas much more quickly.
Hydrogen sulfide
H2S is hydrogen sulphide. Its peculiarity is that it is also a gas. Hydrogen sulfide is very poorly dissolved in water, and also interacts with very many metals. Hydrogen sulphide belongs to the group "weak acids", examples of which we will consider in this article.
H2S has a slightly sweet taste, as well as a very sharp smell of rotten eggs. In nature, it can be found in natural or volcanic gases, and it is released when the protein is rotten.
The properties of acids are very diverse, even ifacid is indispensable in the industry, it can be very unhealthy for human health. This acid is very toxic to humans. When a small amount of hydrogen sulfide is inhaled, a headache develops in the person, severe nausea and dizziness begin. If a person inhales a large amount of H2S, it can lead to convulsions, coma or even instant death.
Sulfuric acid
H2SO4 is a strong sulfuric acid, with which children are introduced to chemistry lessons in the 8th grade. Chemical acids, such as sulfuric acid, are very strong oxidants. H2SO4 acts as an oxidizing agent on very many metals, as well as basic oxides.
H2SO4 when exposed to skin or clothing, causes chemical burns, but it is not as toxic as hydrogen sulphide.
Nitric acid
Strong acids are very important in our world. Examples of such acids are: HCl, H2SO4, HBr, HNO3. HNO3 it is all known nitric acid. It has found wide application in industry, as well as in agriculture. It is used for the manufacture of various fertilizers, in jewelry, in printing photographs, in the manufacture of medicines and dyes, and in the military industry.
Such chemical acids, like nitric, are very harmful to the body. HNO Couples3 they leave ulcers, cause acute inflammation and irritation of the respiratory tract.
Nitrous acid
Nitrogenous acid is very often confused with nitrogen, but there is a difference between them. The fact is that nitrous acid is much weaker than nitrogen, it has completely different properties and effects on the human body.
HNO2 has found wide application in the chemical industry.
Hydrofluoric acid
Hydrofluoric acid (or hydrogen fluoride) is a solution of H2O c HF. The acid formula is HF. Hydrofluoric acid is very actively used in the aluminum industry. It dissolves silicates, etches silicon, silicate glass.
Hydrogen fluoride is very harmful to the bodya person, depending on its concentration, can be an easy drug. If you get on your skin, first, no changes, but after a few minutes, you may get a sharp pain and a chemical burn. Hydrofluoric acid is very harmful to the environment.
Hydrochloric acid
HCl is hydrogen chloride, is a strongacid. Hydrogen chloride preserves the properties of acids belonging to the strong group. The appearance of the acid is clear and colorless, and smokes in the air. Chloride hydrogen is widely used in the metallurgical and food industries.
This acid causes chemical burns, but it is especially dangerous to hit it in the eyes.
Phosphoric acid
Phosphoric acid (H3PO4) is a weak acid in its properties. But even weak acids can have the properties of strong ones. For example, H3PO4 used in industry for restorationiron from rust. In addition, fortified (or orthophosphoric) acid is widely used in agriculture - it produces a variety of various fertilizers.
The properties of acids are very similar - almost all of them are very harmful to the human body, H3PO4 is no exception. For example, this acid also causes severe chemical burns, nosebleeds, and tooth decay.
Carbonic acid
H2CO3 weak acid. It is obtained by dissolving CO2 (carbon dioxide) in H2O (water). Carbonic acid is used in biology and biochemistry.
Density of various acids
Density of acids occupies an important place intheoretical and practical parts of chemistry. Due to knowledge of the density, it is possible to determine the concentration of an acid, solve the calculated chemical problems and add the correct amount of acid for the reaction. The density of any acid varies with concentration. For example, the greater the percentage of concentration, the greater the density.
General properties of acids
Absolutely all acids are complexsubstances (that is, they consist of several elements of the periodic table), and they necessarily include H (hydrogen) in their composition. Next we will consider the chemical properties of acids, which are common:
- All oxygen-containing acids (in the formulaO is present) decompose to form water, as well as acid oxide. And the anoxic ones decompose into simple substances (for example, 2HF decomposes into F2 and H2).
- Acid oxidants interact with all metals in the series of metal activities (only those that are located to the left of H).
- Interact with different salts, but only with those that were formed by an even weaker acid.
By its physical properties of acid abruptlydiffer from each other. After all, they can have a smell and not have it, and also be in very different aggregate states: liquid, gaseous and even solid. Very interesting for studying solid acids. Examples of such acids are: C2H204 and H3BO3.
Concentration
Concentration is a quantity that determines the quantitative composition of any solution. For example, chemists often need to determine how much in diluted acid H2SO4 is pure sulfuric acid. To do this, they pour a small amount of diluted acid into a measuring beaker, weigh and determine the concentration according to the density table. The concentration of acids is closely interrelated with the density, often on the determination of concentration, there are computational problems, where it is necessary to determine the percentage of pure acid in the solution.
The classification of all acids by the number of H atoms in their chemical formula
One of the most popular classifications is the separation of all acids into monobasic, dibasic and, respectively, tribasic acids. Examples of monobasic acids: HNO3 (nitric), HCl (hydrochloric acid), HF(hydrofluoric) and others. These acids are called single-base acids, since only one H atom is present in their composition. There are a lot of such acids, it is impossible to remember absolutely each one. We need only remember that acids are classified according to the number of H atoms in their composition. Dibasic acids are similarly defined. Examples: H2SO4 (sulfuric), H2S (hydrogen sulphide), H2CO3 (coal) and others. Three-base: H3PO4 (phosphoric).
Basic classification of acids
One of the most popular classifications of acids is the separation of them into oxygen-containing and oxygen-free. How to remember, without knowing the chemical formula of the substance, that it is an oxygen-containing acid?
All oxygen-free acids in the compositionthere is no important element O - oxygen, but in the composition there is H. Therefore, the word "hydrogen" is always assigned to their name. HCl is hydrochloric acid, and H2S is hydrogen sulphide.
But by the name of acidic acids, you can write a formula. For example, if the number of O atoms in a substance is 4 or 3, then the suffix -n-, and also the ending -aя- is always added to the name:
- H2SO4 - sulfuric (number of atoms - 4);
- H2SiO3 - silicon (number of atoms - 3).
If the substance is less than three oxygen atoms or three, then the suffix -ist is used in the name:
- HNO2 - nitrogenous;
- H2SO3 - Sulphurous.
Common Properties
All acids have a sour taste and are often slightly metallic. But there are other similar properties that we will now consider.
There are such substances that are calledindicators. The indicators change their color, or the color remains, but its hue changes. This occurs at a time when some other substances, such as acids, are acting on the indicators.
An example of a color change ishabitual to many product, like tea, and citric acid. When a lemon is thrown into tea, the tea gradually begins to brighten noticeably. This is due to the fact that lemon contains citric acid.
There are other examples. Litmus, which in a neutral environment has a lilac color, turns red when hydrochloric acid is added.
When acids interact with metals,in the series of tension to hydrogen, gas bubbles are released - H. However, if a metal is placed in a test tube with acid, which is in the series of tension after H, then no reaction will occur, there will be no gas evolution. So, copper, silver, mercury, platinum and gold with acids will not react.
In this article, we examined the most famous chemical acids, as well as their main properties and differences.
