When you hear the word “salt”, the first association, of course, is cookery, without which any dish would appear tasteless. But this is not the only substance that belongs to the class of chemicals of salt. You can find examples, composition and chemical properties of salts in this article, and also learn how to correctly compose the name of any of them. Before continuing, let's agree, in this article we will consider only inorganic middle salts (obtained by the reaction of inorganic acids with complete replacement of hydrogen).
Definition and chemical composition
One definition of salt is:
- This is a binary compound (i.e., consisting of two parts), which includes metal ions and an acid residue. That is, this substance is the result of the reaction of the acid and hydroxide (oxide) of any metal.
There is another definition:
- This compound, which is the product of the complete or partial replacement of hydrogen ions by acid ions of metal ions (suitable for medium, basic and acidic).
Both definitions are correct, but do not reflect the essence of the process of obtaining salt.
Salt classification
Considering the various representatives of the class of salts, you can see that they are:
- Oxygen-containing (salts of sulfuric, nitric, silicic and other acids, the composition of the acid residue of which includes oxygen and another non-metal).
- Oxygen-free, i.e., salts formed during the reaction of an acid whose acid residue does not contain oxygen - hydrochloric, hydrobromic, hydrogen sulfide and others.
By the number of substituted hydrogens:
- Monobasic: hydrochloric, nitrogen, hydrogen iodide and others. The acid contains one hydrogen ion.
- Dibasic: two hydrogen ions are replaced by metal ions during salt formation. Examples: sulfuric, sulfurous, hydrogen sulfide and others.
- Three-base: in the composition of the acid, three hydrogen ions are replaced by metal ions: phosphoric.
There are other types of classifications by composition and properties, but we will not analyze them, since the purpose of the article is slightly different.
Learning to call correctly
Any substance has a name that is understandable only to residents of a certain region, it is also called trivial. Salt is an example of a colloquial name; according to international nomenclature, it will be called differently. But in a conversation, absolutely anyone who is familiar with the nomenclature of names will understand without problems that this is a substance with the chemical formula NaCl. This salt is a derivative of hydrochloric acid, and its salts are called chlorides, that is, it is called sodium chloride. You just need to learn the names of the salts shown in the table below, and then add the name of the metal that formed the salt.
But the name is so easily compiled if the metal has a constant valency. Now consider a salt (an example with the name), in which the metal with variable valency is FeCl 3. The substance is called ferric chloride. That is the correct name!
| Acid formula | Acid name | Acid Residue (Formula) | Item name | Example and trivial name |
| Hcl | salt | Cl - | chloride | NaCl (table salt, rock salt) |
| Hi | hydrogen iodide | I - | iodide | NaI |
| Hf | hydrogen fluoride | F - | fluoride | NaF |
| HBr | hydrogen bromide | Br - | bromide | NaBr |
| H 2 SO 3 | sulphurous | SO 3 2- | sulfite | Na 2 SO 3 |
| H 2 SO 4 | sulfuric | SO 4 2- | sulfate | CaSO 4 (anhydrite) |
| HCLO | hypochlorous | ClO - | hypochlorite | NaClO |
| HClO 2 | chloride | ClO 2 - | chlorite | NaClO 2 |
| HClO 3 | chlorine | ClO 3 - | chlorate | NaClO 3 |
| HClO 4 | bleach | ClO 4 - | perchlorate | NaClO 4 |
| H 2 CO 3 | coal | CO 3 2- | carbonate | CaCO 3 ( limestone, chalk, marble) |
| HNO 3 | nitrogen | NO 3 - | nitrate | AgNO 3 ( lapis) |
| HNO 2 | nitrogenous | NO 2 - | nitrite | Kno 2 |
| H 3 PO 4 | phosphoric | PO 4 3- | phosphate | Alpo 4 |
| H 2 SiO 3 | silicon | SiO 3 2- | silicate | Na 2 SiO 3 (water glass) |
| HMnO 4 | manganese | MnO 4 - | permanganate | KMnO 4 (potassium permanganate) |
| H 2 CrO 4 | chrome | CrO 4 2- | chromate | CaCrO 4 |
| H 2 s | hydrogen sulfide | S- | sulfide | HgS (cinnabar) |
Chemical properties
As a class, salts by their chemical properties are characterized by the fact that they can interact with alkalis, acids, salts and more active metals:
1. When interacting with alkalis in a solution, a prerequisite for the reaction is the precipitation of one of the resulting substances.
2. When reacted with acids, the reaction proceeds if a volatile acid, insoluble acid or insoluble salt is formed. Examples:
- Coal belongs to volatile acids, as it easily decomposes into water and carbon dioxide: MgCO 3 + 2HCl = MgCl 2 + H 2 O + CO 2.
- Insoluble acid - silicic, is formed as a result of the reaction of silicate with another acid.
- One of the signs of a chemical reaction is precipitation. Which salts precipitate can be found in the solubility table.
3. The interaction of salts with each other occurs only in the case of binding of ions, that is, one of the formed salts precipitates.
4. To determine whether the reaction between the metal and the salt will go, you need to refer to the table of metal stresses (sometimes it is also called a series of activity).
Only more active metals (to the left) can displace metal from salt. An example is the reaction of an iron nail with copper sulfate:
CuSO 4 + Fe = Cu + FeSO 4
Such reactions are characteristic of most representatives of the salt class. But there are more specific reactions in chemistry, the individual properties of the salt are reflective, for example, decomposition during incandescence or the formation of crystalline hydrates. Each salt is individual and unusual in its own way.