Acids are chemical compounds that are capable of donating an electrically charged hydrogen ion (cation) and accepting two interacting electrons, resulting in a covalent bond.
In this article, we will look at the main acids that are studied in the middle grades of general education schools, and also learn a lot of interesting facts about a wide variety of acids. Let's get started.
Acids: types
In chemistry, there are many different acids that have a variety of properties. Chemists distinguish acids by their oxygen content, volatility, solubility in water, strength, stability, belonging to an organic or inorganic class of chemical compounds. In this article, we will look at a table that presents the most famous acids. The table will help you remember the name of the acid and its chemical formula.
| Chemical formula | Acid name |
| H2S | Hydrogen sulfide |
| H2SO4 | Sulfuric |
| HNO3 | Nitrogen |
| HNO2 | Nitrogenous |
| HF | Flavic |
| HCl | S alt |
| H3PO4 | Phosphoric |
| H2CO3 | Coal |
So, everything is clearly visible. This table presents the most famous acids in the chemical industry. The table will help you remember the names and formulas much faster.
Hydrosulfide acid
H2S is hydrogen sulfide acid. Its peculiarity lies in the fact that it is also a gas. Hydrogen sulfide is very poorly soluble in water, and also interacts with many metals. Hydrosulphuric acid belongs to the group of "weak acids", examples of which we will consider in this article.
H2S has a slightly sweet taste and a very strong smell of rotten eggs. In nature, it can be found in natural or volcanic gases, and it is also released when protein rots.
The properties of acids are very diverse, even if the acid is indispensable in industry, it can be very unhe althy for human he alth. This acid is highly toxic to humans. When a small amount of hydrogen sulfide is inhaled, a person wakes up with a headache, severe nausea and dizziness begin. If a person inhales a large amount of H2S, then this can lead to convulsions, coma or even instant death.
Sulfuric acid
H2SO4 - this is a strong sulfuric acid that children get acquainted with in chemistry lessons back in the 8thclass. Chemical acids such as sulfuric are very strong oxidizing agents. H2SO4 acts as an oxidizing agent on many metals as well as basic oxides.
H2SO4 Causes chemical burns on skin or clothing, but is not as toxic as hydrogen sulfide.
Nitric acid
Strong acids are very important in our world. Examples of such acids: HCl, H2SO4, HBr, HNO3. HNO3 is the well-known nitric acid. It has found wide application in industry as well as in agriculture. It is used in the manufacture of various fertilizers, in jewelry, in photographic printing, in the production of drugs and dyes, and in the military industry.
Chemical acids such as nitric acid are very harmful to the body. Vapors of HNO3 leave ulcers, cause acute inflammation and irritation of the respiratory tract.
Nitrous acid
Nitrous acid is often confused with nitric acid, but there is a difference between them. The fact is that nitrous acid is much weaker than nitric acid, it has completely different properties and effects on the human body.
HNO2 is widely used in the chemical industry.
Hydrofluoric acid
Hydrofluoric acid (or hydrogen fluoride) is a solution of H2O with HF. The formula of the acid is HF. Hydrofluoric acid is very actively used in the aluminum industry. It dissolves silicates, poisons silicon, silicateglass.
Hydrogen fluoride is very harmful to the human body, depending on its concentration can be a light drug. When it comes into contact with the skin, at first there are no changes, but after a few minutes, a sharp pain and a chemical burn may appear. Hydrofluoric acid is very harmful to the environment.
Hydrochloric acid
HCl is hydrogen chloride and is a strong acid. Hydrogen chloride retains the properties of acids belonging to the group of strong acids. In appearance, the acid is transparent and colorless, but smokes in air. Hydrogen chloride is widely used in the metallurgical and food industries.
This acid causes chemical burns, but eye contact is especially dangerous.
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 is used in industry to recover iron from rust. In addition, phosphoric (or phosphoric) acid is widely used in agriculture - many different fertilizers are made from it.
The properties of acids are very similar - almost every one of them is 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) into H2O (water). carbonic acidused in biology and biochemistry.
Density of various acids
The density of acids occupies an important place in the theoretical and practical parts of chemistry. Thanks to the knowledge of density, it is possible to determine the concentration of an acid, solve chemical problems, and add the correct amount of acid to complete 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 complex substances (that is, they consist of several elements of the periodic table), while they necessarily include H (hydrogen) in their composition. Next, we look at the chemical properties of acids that are common:
- All oxygen-containing acids (in the formula of which O is present) decompose to form water, as well as an acid oxide. At the same time, oxygen-free decompose into simple substances (for example, 2HF decomposes into F2 and H2).
- Oxidizing acids interact with all metals in the metal activity series (only those located to the left of H).
- React with various s alts, but only with those formed by an even weaker acid.
In their physical properties, acids differ sharply from each other. After all, they can have a smell and not have it, as well as be in a variety of aggregate states: liquid, gaseous and even solid. Solid acids are very interesting for studying. Examples of such acids:C2H204 and H3BO 3.
Concentration
Concentration is a value that determines the quantitative composition of any solution. For example, chemists often need to determine how much pure sulfuric acid is in dilute acid H2SO4. To do this, they pour a small amount of dilute acid into a beaker, weigh it, and determine the concentration from a density table. The concentration of acids is closely related to the density, often there are calculation tasks to determine the concentration, where you need to determine the percentage of pure acid in the solution.
Classification of all acids by the number of H atoms in their chemical formula
One of the most popular classifications is the division of all acids into monobasic, dibasic and, accordingly, tribasic acids. Examples of monobasic acids: HNO3 (nitric), HCl (hydrochloric), HF (hydrofluoric) and others. These acids are called monobasic, since only one H atom is present in their composition. There are many such acids, it is impossible to remember absolutely every one. You just need to remember that acids are also classified by the number of H atoms in their composition. Dibasic acids are defined similarly. Examples: H2SO4 (sulphurous), H2S (hydrogen sulfide), H 2CO3 (coal) and others. Tribasic: H3PO4 (phosphoric).
Basic classification of acids
One of the most popular classifications of acids is their division into oxygen-containing and anoxic acids. How to remember, without knowing the chemical formula of a substance, that it is an oxygen-containing acid?
All oxygen-free acids lack the important element O - oxygen, but contain H. Therefore, the word "hydrogen" is always attributed to their name. HCl is hydrochloric acid and H2S is hydrogen sulfide.
But you can also write a formula by the names of acidic acids. For example, if the number of O atoms in a substance is 4 or 3, then the suffix -n- is always added to the name, as well as the ending -aya-:
- H2SO4 - sulfuric (number of atoms - 4);
- H2SiO3 - silicon (number of atoms - 3).
If the substance has less than three or three oxygen atoms, then the name uses the suffix -ist-:
- HNO2 - nitrogenous;
- H2SO3 - sulphurous.
General Properties
All acids taste sour and often slightly metallic. But there are other similar properties that we will now consider.
There are substances called indicators. Indicators change their color, or the color remains, but its hue changes. This occurs when the indicators are affected by some other substance, such as acids.
An example of a color change is such a familiar product as tea, andlemon acid. When lemon is thrown into tea, the tea gradually begins to noticeably lighten. This is because lemon contains citric acid.
There are other examples. Litmus, which in a neutral medium has a lilac color, turns red when hydrochloric acid is added.
When acids interact with metals that are in the tension series up to hydrogen, gas bubbles are released - H. However, if a metal that is in the tension series after H is placed in a test tube with acid, then no reaction will occur, no gas will be released will. So, copper, silver, mercury, platinum and gold will not react with acids.
In this article, we reviewed the most famous chemical acids, as well as their main properties and differences.
