Acids are such chemical compounds that can give off an electrically charged hydrogen ion (cation), and also take two interacting electrons, as a result of which a covalent bond is formed.
In this article we will consider the basic acids that are studied in the middle grades of secondary schools, and also learn many interesting facts about a variety of acids. Let's get started.
Acids: types
In chemistry, there are many diverse acids that have very different properties. Chemists distinguish acids by oxygen content, volatility, water solubility, strength, stability, and belonging to the organic or inorganic class of chemical compounds. In this article, we will consider a table in which the most famous acids are presented. The table will help to remember the name of the acid and its chemical formula.
| Chemical formula | Acid name |
| H 2 s | Hydrogen sulfide |
| H 2 SO 4 | Sulfuric |
| HNO 3 | Nitric |
| HNO 2 | Nitrous |
| Hf | Floating |
| Hcl | Salt |
| H 3 PO 4 | Phosphoric |
| H 2 CO 3 | Coal |
So, everything is clearly visible. This table shows the most famous acids in the chemical industry. The table will help you remember names and formulas much faster.
Hydrogen sulfide
H 2 S is hydrogen sulfide. Its peculiarity lies in the fact that it is also a gas. Hydrogen sulfide is very poorly soluble in water, and also interacts with very many metals. Hydrogen sulfide belongs to the group of "weak acids", examples of which we will consider in this article.
H 2 S has a slightly sweet taste, as well as a very pungent smell of rotten eggs. In nature, it can be found in natural or volcanic gases, and it is also released during protein decay.
The properties of acids are very diverse, even if acid is indispensable in industry, it can be very harmful for human health. This acid is very toxic to humans. When inhaling a small amount of hydrogen sulfide in a person, a headache awakens, severe nausea and dizziness begin. If a person inhales a large amount of H 2 S, then this can lead to convulsions, coma, or even instant death.
Sulfuric acid
H 2 SO 4 is a strong sulfuric acid that children meet in chemistry classes as early as 8th grade. Chemical acids, such as sulfuric, are very powerful oxidizing agents. H 2 SO 4 acts as an oxidizing agent on so many metals, as well as basic oxides.
H 2 SO 4, if it comes in contact with skin or clothing, causes chemical burns, but it is not as toxic as hydrogen sulfide.
Nitric acid
Strong acids are very important in our world. Examples of such acids: HCl, H 2 SO 4 , HBr, HNO 3 . HNO 3 is a well-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 the printing of photographs, in the production of medicines and dyes, as well as in the military industry.
Chemical acids such as nitric acid are very harmful to the body. HNO 3 vapors leave ulcers, causing acute inflammation and respiratory tract irritation.
Nitrous acid
Nitric 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.
HNO 2 is widely used in the chemical industry.
Hydrofluoric acid
Hydrofluoric acid (or hydrogen fluoride) is a solution of H 2 O with HF. The acid formula is HF. Hydrofluoric acid is very actively used in the aluminum industry. It dissolves silicates, etch silicon, silicate glass.
Hydrogen fluoride is very harmful to the human body, depending on its concentration it can be a light drug. If it gets on the skin, at first no changes, but after a few minutes, sharp pain and a chemical burn may appear. Hydrofluoric acid is very harmful to the outside world.
Hydrochloric acid
HCl is hydrogen chloride, is a strong acid. Hydrogen chloride retains the properties of acids belonging to the group of strong. The acid looks transparent and colorless, and smokes in air. Hydrogen chloride is widely used in the metallurgical and food industries.
This acid causes chemical burns, but it is especially dangerous if it gets into the eyes.
Phosphoric acid
Phosphoric acid (H 3 PO 4 ) is a weak acid in its properties. But even weak acids can have the properties of strong ones. For example, H 3 PO 4 is used in industry to reduce iron from rust. In addition, forcephoric (or orthophosphoric) acid is widely used in agriculture - many diverse fertilizers are made from it.
The properties of acids are very similar - almost every one of them is very harmful to the human body, H 3 PO 4 is no exception. For example, this acid also causes severe chemical burns, nosebleeds, and tooth decay.
Carbonic acid
H 2 CO 3 is a weak acid. It is obtained by dissolving CO 2 (carbon dioxide) in H 2 O (water). Carbonic acid is used in biology and biochemistry.
The 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 the density, it is possible to determine the concentration of a particular acid, solve the calculated chemical problems, and add the correct amount of acid to carry out 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), and they necessarily include H (hydrogen) in their composition. Next, we consider the chemical properties of acids that are common:
- All oxygen-containing acids (in the formula of which O is present) upon decomposition form water, as well as acid oxide. In this case, oxygen-free decompose into simple substances (for example, 2HF decomposes into F 2 and H 2 ).
- Oxidizing acids interact with all metals in a series of metal activity (only those located to the left of H).
- Interact with various salts, but only with those that were formed by an even weaker acid.
Acids differ sharply in their physical properties. 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 are: C 2 H 2 0 4 and H 3 BO 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 H 2 SO 4 . To do this, they pour a small amount of diluted acid into a measuring cup, weigh and determine the concentration according to the density table. The concentration of acids is closely correlated with the density, often for the determination of concentration there are calculation problems where you need to determine the percentage of pure acid in solution.
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, accordingly, tribasic acids. Examples of monobasic acids: HNO 3 (nitric), HCl (hydrochloric), HF (hydrogen fluoride) and others. These acids are called monobasic, since there is only one H atom in their composition. There are many such acids, it is impossible to remember absolutely every one. You just need to remember that acids are classified by the number of H atoms in their composition. Dibasic acids are similarly determined. Examples: H 2 SO 4 (sulfuric), H 2 S (hydrogen sulfide), H 2 CO 3 (coal) and others. Tribasic: H 3 PO 4 (phosphoric).
Basic classification of acids
One of the most popular classifications of acids is their separation 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 composition lack an important element O - oxygen, but in the composition there is H. Therefore, the word "hydrogen" is always attributed to their name. HCl is hydrochloric acid, and H 2 S is hydrogen sulfide.
But also by the names of acid-containing 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 the ending -aya- are always added to the name:
- H 2 SO 4 - sulfuric (number of atoms - 4);
- H 2 SiO 3 - silicon (number of atoms - 3).
If the substance has less than three oxygen atoms or three, then the suffix -ist- is used in the name:
- HNO 2 is nitrogenous;
- H 2 SO 3 - sulphurous.
General properties
All acids taste sour and often a little metallic. But there are other similar properties that we will now consider.
There are substances called indicators. The indicators change their color, or the color remains, but its hue changes. This happens when some other substances, such as acids, act on the indicators.
An example of a color change is a product so familiar to many as tea and citric acid. When lemon is thrown into tea, tea gradually begins to noticeably lighten. 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, with the addition of hydrochloric acid turns red.
The interaction of acids with metals in a range of tension up to hydrogen produces gas bubbles - H. However, if a metal is placed in a test tube with acid, which is in a row of tension after H, then no reaction will occur, gas will not be released. So, copper, silver, mercury, platinum and gold will not react with acids.
In this article, we examined the most famous chemical acids, as well as their main properties and differences.