Decomposition of insoluble salts. Salts: examples, composition, names and chemical properties

Salts are organic and inorganic chemicals of complex composition. In chemical theory there is no strict and definitive definition of salts. They can be described as compounds:
- consisting of anions and cations;
- obtained as a result of the interaction of acids and bases;
- consisting of acidic residues and metal ions.

Acid residues can be associated not with metal atoms, but with ammonium ions (NH 4) +, phosphonium (PH 4) +, hydroxonium (H 3 O) + and some others.

Salt types

- Acid, medium, basic. If in an acid all hydrogen protons are replaced by metal ions, then such salts are called medium salts, for example, NaCl. If hydrogen is only partially substituted, then such salts are acidic, for example. KHSO 4 and NaH 2 PO 4 . If the hydroxyl groups (OH)-bases are not completely replaced by an acidic residue, then the salt is basic, for example. CuCl(OH), Al(OH)SO 4 .

— Simple, double, mixed. Simple salts consist of one metal and one acid residue, such as K 2 SO 4 . There are two metals in double salts, for example KAl(SO 4) 2 . In mixed salts, two acid residues, for example. AgClBr.

— Organic and inorganic.
- Complex salts with a complex ion: K 2, Cl 2 and others.
— Crystal hydrates and crystal solvates.
— Crystalline hydrates with molecules of water of crystallization. CaSO 4 * 2H 2 O.
— Crystal solvates with solvent molecules. For example, LiCl in liquid ammonia NH 3 gives LiCl*5NH 3 solvate.
— Oxygen-containing and not containing oxygen.
- Internal, otherwise called bipolar ions.

Properties

Most salts are solids with a high melting point and do not conduct electricity. Solubility in water is an important characteristic; on its basis, reagents are divided into water-soluble, slightly soluble and insoluble. Many salts are soluble in organic solvents.

Salts react:
- with more active metals;
- with acids, bases, other salts, if during the interaction substances are obtained that do not participate in the further reaction, for example, gas, insoluble precipitate, water. Decompose when heated, hydrolyze in water.

In nature, salts are widely distributed in the form of minerals, brines, salt deposits. They are also mined from sea water, mountain ores.

Salts are essential for the human body. Iron salts are needed to replenish hemoglobin, calcium - are involved in the formation of the skeleton, magnesium - regulate the activity of the gastrointestinal tract.

The use of salts

Salts are actively used in production, everyday life, agriculture, medicine, food industry, chemical synthesis and analysis, and in laboratory practice. Here are just a few of their areas of application:

- Sodium, potassium, calcium and ammonium nitrates (nitrate); calcium phosphate, potassium chloride is a raw material for the production of fertilizers.
— Sodium chloride is necessary for the production of edible table salt, it is used in the chemical industry for the production of chlorine, soda, caustic soda.
Sodium hypochlorite is a popular bleach and water disinfectant.
— Salts of acetic acid (acetates) are used in the food industry as preservatives (potassium and calcium acetate); in medicine for the manufacture of medicines, in the cosmetic industry (sodium acetate), for many other purposes.
— Potassium alum and potassium chromium alum are in demand in medicine and the food industry; for dyeing fabrics, leather, furs.
— Many salts are used as fixants to determine the chemical composition of substances, water quality, acidity levels, etc.

Our store offers a wide range of salts, both organic and inorganic.

A large number of reactions leading to the formation of salts are known. We present the most important of them.

1. Reaction of acids with bases (neutralization reaction):

NaOH + HNO 3 = NANO 3 + H 2 ABOUT

Al(Oh) 3 + 3HC1 =AlCl 3 + 3H 2 ABOUT

2. The interaction of metals with acids:

Fe + 2HCl = FeCl 2 + H 2 

Zn+ H 2 SABOUT 4 razb. = ZnSO 4 + H 2 

3. Interaction of acids with basic and amphoteric oxides:

WITHuO+ H 2 SO 4 = CUSO 4 + H 2 ABOUT

ZnO + 2 HCl = ZnWITHl 2 + H 2 ABOUT

4. The interaction of acids with salts:

FeCl 2 + H 2 S = FeS + 2 HCl

AgNO 3 + HCI = AgCl + HNO 3

Ba(NO 3 ) 2 + H 2 SO 4 = BaSO 4  + 2HNO 3

5. The interaction of solutions of two different salts:

BaCl 2 + Na 2 SO 4 = WaSO 4  + 2Nasl

Pb(NO 3 ) 2 + 2NaCl =RbWITH1 2  + 2NaNO 3

6. Interaction of bases with acidic oxides (alkalis with amphoteric oxides):

Ca(OH) 2 + CO 2 = CaCO 3  + H 2 ABOUT,

2 Nand he (TV) + ZnO Na 2 ZnO 2 + H 2 ABOUT

7. Interaction of basic oxides with acid ones:

SaO+SiO 2 SaSiO 3

Na 2 O+SO 3 = Na 2 SO 4

8. Interaction of metals with non-metals:

2K + C1 2 = 2KS1

Fe+S FeS

9. The interaction of metals with salts.

Cu + Hg(NO 3 ) 2 = Hg + Cu(NO 3 ) 2

Pb(NO 3 ) 2 + Zn =Rb + Zn(NO 3 ) 2

10. Interaction of alkali solutions with salt solutions

CuCl 2 + 2NaOH = Cu(OH) 2 ↓+ 2NaCl

NaHCO 3 + NaOH = Na 2 CO 3 + H 2 O

1. The use of salts.

A number of salts are compounds necessary in significant quantities to ensure the vital activity of animal and plant organisms (salts of sodium, potassium, calcium, as well as salts containing the elements nitrogen and phosphorus). Below, using examples of individual salts, the fields of application of representatives of this class of inorganic compounds, including in the oil industry, are shown.

NaC1- sodium chloride (edible salt, table salt). The breadth of the use of this salt is evidenced by the fact that the world production of this substance is more than 200 million tons.

This salt is widely used in the food industry, serves as a raw material for the production of chlorine, hydrochloric acid, sodium hydroxide, soda ash (Na 2 CO 3 ). Sodium chloride finds a variety of uses in the oil industry, for example, as an additive in drilling fluids to increase density, prevent the formation of caverns during well drilling, as a regulator of the setting time of cement grouting compositions, to lower the freezing point (antifreeze) of drilling and cement slurries.

KS1- potassium chloride. Included in drilling fluids that help maintain the stability of well walls in clayey rocks. In significant quantities, potassium chloride is used in agriculture as a macrofertilizer.

Na 2 CO 3 - sodium carbonate (soda). Included in mixtures for the production of glass, detergents. Reagent for increasing the alkalinity of the environment, improving the quality of clays for clay drilling fluids. It is used to remove the hardness of water during its preparation for use (for example, in boilers), it is widely used for the purification of natural gas from hydrogen sulfide and for the production of reagents for drilling and cement slurries.

Al 2 (SO 4 ) 3 - aluminum sulfate. A component of drilling fluids, a coagulant for water purification from fine suspended particles, a component of viscoelastic mixtures for isolating loss zones in oil and gas wells.

NA 2 IN 4 ABOUT 7 - sodium tetraborate (borax). It is an effective agent - retarder of setting of cement mortars, inhibitor of thermo-oxidative destruction of protective reagents based on cellulose ethers.

BASABOUT 4 - barium sulfate (barite, heavy spar). It is used as a weighting agent (  4.5 g / cm 3) for drilling and cement slurries.

Fe 2 SO 4 - ferrous sulfate (P) (iron vitriol). It is used for the preparation of ferrochrome lignosulfonate - a reagent-stabilizer of drilling fluids, a component of high-performance oil-based emulsion drilling fluids.

FeC1 3 - iron chloride (III). In combination with alkali, it is used to purify water from hydrogen sulfide when drilling wells with water, for injection into hydrogen sulfide-containing formations in order to reduce their permeability, as an additive to cements in order to increase their resistance to hydrogen sulfide, to purify water from suspended particles.

CaCO 3 - calcium carbonate in the form of chalk, limestone. It is a raw material for the production of quicklime CaO and slaked lime Ca(OH) 2 . Used in metallurgy as a flux. It is used when drilling oil and gas wells as a weighting agent and filler of drilling fluids. Calcium carbonate in the form of marble with a certain particle size is used as a proppant in hydraulic fracturing of productive formations in order to increase oil recovery.

CaSO 4 - calcium sulfate. In the form of alabaster (2СаSO 4 · Н 2 О) it is widely used in construction; it is part of fast-hardening binder mixtures for isolating absorption zones. When added to drilling fluids in the form of anhydrite (CaSO 4) or gypsum (CaSO 4 · 2H 2 O), it gives stability to drilled clayey rocks.

CaCl 2 - calcium chloride. It is used for the preparation of drilling and grouting solutions for drilling out unstable rocks, greatly reduces the freezing point of solutions (antifreeze). It is used to create high-density muds that do not contain a solid phase, effective for opening productive formations.

NA 2 SiABOUT 3 - sodium silicate (soluble glass). It is used for fixing unstable soils, for preparing quick-setting mixtures for isolating absorption zones. It is used as a metal corrosion inhibitor, a component of some drilling cement and buffer solutions.

AgNO 3 - silver nitrate. It is used for chemical analysis, including formation waters and drilling mud filtrates for the content of chlorine ions.

Na 2 SO 3 - sodium sulfite. It is used for chemical removal of oxygen (deaeration) from water in order to combat corrosion during sewage injection. For inhibition of thermo-oxidative degradation of protective reagents.

Na 2 Cr 2 ABOUT 7 - sodium bichromate. It is used in the oil industry as a high-temperature viscosity reducer for drilling fluids, an aluminum corrosion inhibitor, for the preparation of a number of reagents.

Modern chemical science is a wide variety of branches, and each of them, in addition to the theoretical base, is of great applied and practical importance. Whatever you touch, everything around is the products of chemical production. The main sections are inorganic and organic chemistry. Let us consider what main classes of substances are classified as inorganic and what properties they have.

Main categories of inorganic compounds

These include the following:

1. Oxides.
2. Salt.
3. Foundations.
4. Acids.

Each of the classes is represented by a wide variety of inorganic compounds and is important in almost any structure of human economic and industrial activity. All the main properties characteristic of these compounds, being in nature and obtaining are studied in the school chemistry course without fail, in grades 8-11.

There is a general table of oxides, salts, bases, acids, which presents examples of each of the substances and their state of aggregation, being in nature. It also shows interactions that describe chemical properties. However, we will consider each of the classes separately and in more detail.

Group of compounds - oxides

4. Reactions, as a result of which elements change CO

Me + n O + C = Me 0 + CO

1. Reagent water: acid formation (SiO 2 exception)

KO + water = acid

2. Reactions with bases:

CO 2 + 2CsOH \u003d Cs 2 CO 3 + H 2 O

3. Reactions with basic oxides: salt formation

P 2 O 5 + 3MnO \u003d Mn 3 (PO 3) 2

4. OVR reactions:

CO 2 + 2Ca \u003d C + 2CaO,

They show dual properties, interact according to the principle of the acid-base method (with acids, alkalis, basic oxides, acid oxides). They do not interact with water.

1. With acids: formation of salts and water

AO + acid \u003d salt + H 2 O

2. With bases (alkalis): formation of hydroxo complexes

Al 2 O 3 + LiOH + water \u003d Li

3. Reactions with acid oxides: preparation of salts

FeO + SO 2 \u003d FeSO 3

4. Reactions with RO: formation of salts, fusion

MnO + Rb 2 O = double salt Rb 2 MnO 2

5. Fusion reactions with alkalis and alkali metal carbonates: formation of salts

Al 2 O 3 + 2LiOH \u003d 2LiAlO 2 + H 2 O

Each higher oxide, formed both by a metal and a non-metal, when dissolved in water, gives a strong acid or alkali.

Acids organic and inorganic

In the classical sound (based on the positions of ED - electrolytic dissociation - Svante Arrhenius), acids are compounds that dissociate into H + cations and anions of An acid residues in an aqueous medium. Today, however, acids have been carefully studied under anhydrous conditions, so there are many different theories for hydroxides.

Empirical formulas of oxides, bases, acids, salts are made up only of symbols, elements and indices indicating their amount in a substance. For example, inorganic acids are expressed by the formula H + acid residue n-. Organic substances have a different theoretical mapping. In addition to the empirical one, it is possible to write down a full and abbreviated structural formula for them, which will reflect not only the composition and amount of the molecule, but also the arrangement of atoms, their relationship to each other and the main functional group for carboxylic acids -COOH.

In the inorganic, all acids are divided into two groups:

• anoxic - HBr, HCN, HCL and others;
• oxygen-containing (oxo acids) - HClO 3 and everything where there is oxygen.

Also, inorganic acids are classified by stability (stable or stable - everything except carbonic and sulphurous, unstable or unstable - carbonic and sulphurous). By strength, acids can be strong: sulfuric, hydrochloric, nitric, perchloric and others, as well as weak: hydrogen sulfide, hypochlorous and others.

Organic chemistry does not offer such diversity at all. Acids that are organic in nature are carboxylic acids. Their common feature is the presence of a functional group -COOH. For example, HCOOH (antic), CH 3 COOH (acetic), C 17 H 35 COOH (stearic) and others.

There are a number of acids, which are especially carefully emphasized when considering this topic in a school chemistry course.

1. Salt.
2. Nitrogen.
3. Orthophosphoric.
4. Hydrobromic.
5. Coal.
6. Iodine.
7. Sulfuric.
8. Acetic, or ethane.
9. Butane or oil.
10. Benzoic.

These 10 acids in chemistry are the fundamental substances of the corresponding class both in the school course and in general in industry and synthesis.

Properties of inorganic acids

The main physical properties should be attributed primarily to a different state of aggregation. After all, there are a number of acids that have the form of crystals or powders (boric, orthophosphoric) under normal conditions. The vast majority of known inorganic acids are different liquids. Boiling and melting points also vary.

Acids can cause severe burns, as they have the power to destroy organic tissues and skin. Indicators are used to detect acids:

• methyl orange (in normal environment - orange, in acids - red),
• litmus (in neutral - violet, in acids - red) or some others.

The most important chemical properties include the ability to interact with both simple and complex substances.

When interacting with metals, not all acids react in the same way. Chemistry (grade 9) at school involves a very shallow study of such reactions, however, even at this level, the specific properties of concentrated nitric and sulfuric acid when interacting with metals are considered.

Hydroxides: alkalis, amphoteric and insoluble bases

Oxides, salts, bases, acids - all these classes of substances have a common chemical nature, which is explained by the structure of the crystal lattice, as well as the mutual influence of atoms in the composition of molecules. However, if for oxides it was possible to give a very specific definition, then for acids and bases it is more difficult to do so.

Just like acids, according to the ED theory, bases are substances that can decompose in an aqueous solution into metal cations Me n + and anions of hydroxo groups OH -.

• Soluble or alkali (strong bases that change the color of the indicators). Formed by metals I, II groups. Example: KOH, NaOH, LiOH (that is, elements of only the main subgroups are taken into account);
• Slightly soluble or insoluble (medium strength, do not change the color of the indicators). Example: magnesium hydroxide, iron (II), (III) and others.
• Molecular (weak bases, in an aqueous medium they reversibly dissociate into ions-molecules). Example: N 2 H 4, amines, ammonia.
• Amphoteric hydroxides (show dual basic-acid properties). Example: beryllium, zinc and so on.

Each group represented is studied in the school chemistry course in the "Foundations" section. Chemistry grades 8-9 involves a detailed study of alkalis and sparingly soluble compounds.

The main characteristic properties of the bases

All alkalis and sparingly soluble compounds are found in nature in a solid crystalline state. At the same time, their melting points are, as a rule, low, and poorly soluble hydroxides decompose when heated. The base color is different. If the alkalis are white, then the crystals of sparingly soluble and molecular bases can be of very different colors. The solubility of most compounds of this class can be viewed in the table, which presents the formulas of oxides, bases, acids, salts, shows their solubility.

Alkalis are able to change the color of indicators as follows: phenolphthalein - raspberry, methyl orange - yellow. This is ensured by the free presence of hydroxo groups in solution. That is why sparingly soluble bases do not give such a reaction.

The chemical properties of each group of bases are different.

These are the most chemical properties that bases exhibit. The chemistry of bases is quite simple and obeys the general laws of all inorganic compounds.

Class of inorganic salts. Classification, physical properties

Based on the provisions of the ED, salts can be called inorganic compounds that dissociate in an aqueous solution into metal cations Me + n and anions of acid residues An n-. So you can imagine salt. Chemistry gives more than one definition, but this is the most accurate.

At the same time, according to their chemical nature, all salts are divided into:

• Acidic (containing a hydrogen cation). Example: NaHSO4.
• Basic (having a hydroxo group). Example: MgOHNO 3 , FeOHCL 2.
• Medium (consist only of a metal cation and an acid residue). Example: NaCL, CaSO 4.
• Double (include two different metal cations). Example: NaAl(SO 4) 3.
• Complex (hydroxocomplexes, aquacomplexes and others). Example: K 2 .

The formulas of salts reflect their chemical nature, and also speak of the qualitative and quantitative composition of the molecule.

Oxides, salts, bases, acids have different solubility, which can be seen in the corresponding table.

If we talk about the state of aggregation of salts, then you need to notice their uniformity. They exist only in a solid, crystalline or powdered state. The color scheme is quite varied. Solutions of complex salts, as a rule, have bright saturated colors.

Chemical interactions for the class of medium salts

They have similar chemical properties of bases, acids, salts. Oxides, as we have already considered, differ somewhat from them in this factor.

In total, 4 main types of interactions can be distinguished for medium salts.

I. Interaction with acids (only strong in terms of ED) with the formation of another salt and a weak acid:

KCNS + HCL = KCL + HCNS

II. Reactions with soluble hydroxides with the appearance of salts and insoluble bases:

CuSO 4 + 2LiOH = 2LiSO 4 soluble salt + Cu(OH) 2 insoluble base

III. Interaction with another soluble salt to form an insoluble salt and a soluble one:

PbCL 2 + Na 2 S = PbS + 2NaCL

IV. Reactions with metals to the left of the one that forms the salt in the EHRNM. In this case, the metal entering into the reaction should not, under normal conditions, interact with water:

Mg + 2AgCL = MgCL 2 + 2Ag

These are the main types of interactions that are characteristic of medium salts. The formulas of complex, basic, double and acidic salts speak for themselves about the specificity of the manifested chemical properties.

The formulas of oxides, bases, acids, salts reflect the chemical nature of all representatives of these classes of inorganic compounds, and in addition, give an idea of ​​the name of the substance and its physical properties. Therefore, special attention should be paid to their writing. A huge variety of compounds offers us a generally amazing science - chemistry. Oxides, bases, acids, salts - this is only part of the vast variety.

salts complex substances are called, the molecules of which consist of metal atoms and acid residues (sometimes they may contain hydrogen). For example, NaCl is sodium chloride, CaSO 4 is calcium sulfate, etc.

Practically All salts are ionic compounds therefore, in salts, ions of acid residues and metal ions are interconnected:

Na + Cl - - sodium chloride

Ca 2+ SO 4 2– - calcium sulfate, etc.

Salt is a product of partial or complete replacement of acid hydrogen atoms by a metal. Hence, the following types of salts are distinguished:

1. Medium salts- all hydrogen atoms in the acid are replaced by a metal: Na 2 CO 3, KNO 3, etc.

2. Acid salts- not all hydrogen atoms in the acid are replaced by a metal. Of course, acid salts can only form dibasic or polybasic acids. Monobasic acids cannot give acid salts: NaHCO 3, NaH 2 PO 4, etc. d.

3. Double salts- hydrogen atoms of a dibasic or polybasic acid are replaced not by one metal, but by two different ones: NaKCO 3, KAl(SO 4) 2, etc.

4. Basic salts can be considered as products of incomplete or partial substitution of hydroxyl groups of bases by acidic residues: Al(OH)SO 4 , Zn(OH)Cl, etc.

According to international nomenclature, the name of the salt of each acid comes from the Latin name of the element. For example, salts of sulfuric acid are called sulfates: CaSO 4 - calcium sulfate, Mg SO 4 - magnesium sulfate, etc.; salts of hydrochloric acid are called chlorides: NaCl - sodium chloride, ZnCI 2 - zinc chloride, etc.

The particle “bi” or “hydro” is added to the name of salts of dibasic acids: Mg (HCl 3) 2 - magnesium bicarbonate or bicarbonate.

Provided that in a tribasic acid only one hydrogen atom is replaced by a metal, then the prefix "dihydro" is added: NaH 2 PO 4 - sodium dihydrogen phosphate.

Salts are solid substances that have a wide range of solubility in water.

Chemical properties of salts

The chemical properties of salts are determined by the properties of the cations and anions that are part of their composition.

1. Some salts decompose when calcined:

CaCO 3 \u003d CaO + CO 2

2. React with acids to form a new salt and a new acid. For this reaction to occur, it is necessary that the acid be stronger than the salt that the acid acts on:

2NaCl + H 2 SO 4 → Na 2 SO 4 + 2HCl.

3. Interact with bases, forming a new salt and a new base:

Ba(OH) 2 + MgSO 4 → BaSO 4 ↓ + Mg(OH) 2 .

4. Interact with each other with the formation of new salts:

NaCl + AgNO 3 → AgCl + NaNO 3 .

5. Interact with metals, which are in the range of activity to the metal that is part of the salt:

Fe + CuSO 4 → FeSO 4 + Cu↓.

Do you have any questions? Want to know more about salts?
To get help from a tutor -.
The first lesson is free!

blog.site, with full or partial copying of the material, a link to the source is required.

When you hear the word "salt", the first association is, of course, cooking, without which any dish will seem tasteless. But this is not the only substance that belongs to the class of salt chemicals. You can find examples, composition and chemical properties of salts in this article, as well as learn how to correctly compose the name of any of them. Before proceeding, let's agree that in this article we will consider only inorganic medium salts (obtained by the reaction of inorganic acids with complete replacement of hydrogen).

Definition and chemical composition

One of the definitions of salt is:

• (i.e., consisting of two parts), which includes metal ions and an acid residue. That is, it is a substance resulting from the reaction of an acid and a hydroxide (oxide) of any metal.

There is another definition:

• This compound is a product of complete or partial replacement of hydrogen ions of an acid with metal ions (suitable for medium, basic and acidic).

Both definitions are correct, but do not reflect the whole essence of the salt production process.

Salt classification

Considering various representatives of the class of salts, you can see that they are:

• Oxygen-containing (salts of sulfuric, nitric, silicic and other acids, the acid residue of which includes oxygen and another non-metal).
• Anoxic, i.e., salts formed during the reaction, the residue of which does not contain oxygen - hydrochloric, hydrobromic, hydrogen sulfide and others.

By the number of substituted hydrogens:

• Monobasic: hydrochloric, nitric, hydroiodic and others. An acid contains one hydrogen ion.
• Dibasic: Two hydrogen ions are replaced by metal ions in the formation of a salt. Examples: sulfuric, sulfurous, hydrogen sulfide and others.
• Tribasic: 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 name correctly

Any substance has a name that is understandable only to residents of a certain region, it is also called trivial. Table salt is an example of a colloquial name; according to international nomenclature, it will be called differently. But in a conversation, absolutely any person familiar with the nomenclature of names will understand without any problems that we are talking about 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 given in the table below, and then add the name of the metal that formed the salt.

But the name is so simply compiled if the metal has a constant valence. And now let's look at the name), in which the metal with variable valency is FeCl 3. The substance is called ferric chloride. That is the correct name!

Chemical properties

As a class, salts are characterized by their chemical properties in that they can interact with alkalis, acids, salts and more active metals:

1. When interacting with alkalis in solution, a prerequisite for the reaction is the precipitation of one of the resulting substances.

2. When interacting with acids, the reaction proceeds if a volatile acid, an insoluble acid, or an insoluble salt is formed. Examples:

• Volatile acids include carbonic, since it easily decomposes into water and carbon dioxide: MgCO 3 + 2HCl \u003d MgCl 2 + H 2 O + CO 2.
• The insoluble acid, silicic, is formed by the reaction of a silicate with another acid.
• One of the signs of a chemical reaction is the formation of a precipitate. What salts can be seen in the solubility table.

3. The interaction of salts with each other occurs only in the case of binding of ions, i.e. 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 metal stress table (sometimes also called the activity series).

Only more active metals (located to the left) can displace the metal from the salt. An example is the reaction of an iron nail with blue vitriol:

CuSO 4 + Fe \u003d Cu + FeSO 4

Such reactions are characteristic of most representatives of the class of salts. But there are also more specific reactions in chemistry, the individual reflecting properties of salt, for example, decomposition upon incandescence or the formation of crystalline hydrates. Each salt is individual and unusual in its own way.