The chemical properties of acids are examples. Acids: classification and chemical properties

Acids- complex substances consisting of one or more hydrogen atoms capable of being replaced by metal atoms, and acid residues.

Classification of acids

1. By the number of hydrogen atoms: the number of hydrogen atoms ( n ) determines the basicity of acids:

n= 1 monobasic

n= 2 dibasic

n= 3 three-base

2. By composition:

a) Table of oxygen-containing acids, acidic residues and corresponding acidic oxides:

Acid (H n A)	Acid residue (A)	Corresponding acidic oxide
H 2 SO 4 sulfuric	SO 4 (II) sulfate	SO 3 sulfur oxide (VI)
HNO 3 nitrogen	NO 3 (I) nitrate	N 2 O 5 nitric oxide (V)
HMnO 4 manganese	MnO 4 (I) permanganate	Mn 2 O 7 manganese oxide ( Vii)
H 2 SO 3 sulphurous	SO 3 (II) sulfite	SO 2 sulfur (IV) oxide
H 3 PO 4 orthophosphoric	PO 4 (III) orthophosphate	P 2 O 5 phosphorus (V) oxide
HNO 2 nitrogenous	NO 2 (I) nitrite	N 2 O 3 nitric oxide (III)
H 2 CO 3 coal	CO 3 (II) carbonate	CO 2 carbon monoxide ( IV)
H 2 SiO 3 silicon	SiO 3 (II) silicate	SiO 2 silicon oxide (IV)
НСlO hypochlorous	СlO (I) hypochlorite	С l 2 O chlorine oxide (I)
HClO 2 chloride	СlO 2 (I) chlorite	С l 2 O 3 chlorine (III) oxide
HClO 3 chloric	СlO 3 (I) chlorate	С l 2 O 5 chlorine oxide (V)
HClO 4 chloric	СlO 4 (I) perchlorate	С l 2 O 7 chlorine oxide (VII)

b) Table of anoxic acids

Acid (H n A)	Acid residue (A)
HCl hydrochloric, hydrochloric	Cl (I) chloride
H 2 S hydrogen sulfide	S (II) sulfide
HBr hydrogen bromide	Br (I) bromide
HI hydroiodine	I (I) iodide
HF hydrofluoric, hydrofluoric	F (I) fluoride

Physical properties of acids

Many acids, such as sulfuric, nitric, hydrochloric, are colorless liquids. also known solid acids: phosphoric, metaphosphoric HPO 3 boric H 3 BO 3 ... Almost all acids are water soluble. An example of an insoluble acid is silicic H 2 SiO 3 ... Acid solutions taste sour. For example, the acids they contain give a sour taste to many fruits. Hence the names of acids: citric, malic, etc.

Methods for obtaining acids

anoxic	oxygenated
HCl, HBr, HI, HF, H 2 S	HNO 3, H 2 SO 4 and others
OBTAINING
1. Direct interaction of non-metals H 2 + Cl 2 = 2 HCl	1. Acid Oxide + Water = Acid SO 3 + H 2 O = H 2 SO 4
2. Exchange reaction between salt and less volatile acid 2 NaCl (TV) + H 2 SO 4 (conc.) = Na 2 SO 4 + 2HCl

Chemical properties of acids

1. Change the color of the indicators

Indicator name	Neutral environment	Acidic environment
Litmus	Purple	Red
Phenolphthalein	Colorless	Colorless
Methyl Orange	Orange	Red
Universal indicator paper	Orange	Red

2.React with metals in the range of activity up to H 2

(excl. HNO 3 -Nitric acid)

Video "Interaction of acids with metals"

Me + ACID = SALT + H 2 (p. substitution)

Zn + 2 HCl = ZnCl 2 + H 2

3.With basic (amphoteric) oxides - metal oxides

Video "Interaction of metal oxides with acids"

Me x O y + ACID = SALT + H 2 O (p. exchange)

4. React with bases – neutralization reaction

ACID + BASE = SALT + H 2 O (p. exchange)

H 3 PO 4 + 3 NaOH = Na 3 PO 4 + 3 H 2 O

5. React with salts of weak, volatile acids - if acid is formed, precipitated or gas is released:

2 NaCl (TV) + H 2 SO 4 (conc.) = Na 2 SO 4 + 2HCl ( R . exchange )

Video "Interaction of acids with salts"

6. Decomposition of oxygen-containing acids when heated

(excl. H 2 SO 4 ; H 3 PO 4 )

ACID = ACID OXIDE + WATER (p. decomposition)

Remember!Unstable acids (carbonic and sulfurous) - decompose into gas and water:

H 2 CO 3 ↔ H 2 O + CO 2

H 2 SO 3 ↔ H 2 O + SO 2

Hydrogen sulfide acid in products released in the form of gas:

CaS + 2HCl = H 2 S+ CaCl 2

ASSIGNMENT TASKS

# 1. Distribute chemical formulas acids in the table. Give them names:

LiOH, Mn 2 O 7, CaO, Na 3 PO 4, H 2 S, MnO, Fe (OH) 3, Cr 2 O 3, HI, HClO 4, HBr, CaCl 2, Na 2 O, HCl, H 2 SO 4, HNO 3, HMnO 4, Ca (OH) 2, SiO 2, Acids

Demon-sour

relatives

Oxygen-containing

soluble

unbreakable

one-

the main

two-main

three-main

No. 2. Make the reaction equations:

Ca + HCl

Na + H 2 SO 4

Al + H 2 S

Ca + H 3 PO 4
What are the reaction products?

No. 3. Make up the reaction equations, name the products:

Na 2 O + H 2 CO 3

ZnO + HCl

CaO + HNO 3

Fe 2 O 3 + H 2 SO 4

No. 4. Make up the equations for the reactions of the interaction of acids with bases and salts:

KOH + HNO 3

NaOH + H 2 SO 3

Ca (OH) 2 + H 2 S

Al (OH) 3 + HF

HCl + Na 2 SiO 3

H 2 SO 4 + K 2 CO 3

HNO 3 + CaCO 3

What are the reaction products?

SIMULATORS

Exercise machine number 1. "Formulas and names of acids"

Exercise machine number 2. "Mapping: acid formula - oxide formula"

Safety Precautions - First Aid for Skin Contact with Acids

Safety precautions -

Substances that dissociate in solutions to form hydrogen ions are called.

Acids are classified according to their strength, basicity, and the presence or absence of oxygen in the acid.

By strengthacids are divided into strong and weak. The most important strong acids are nitric HNO 3, sulfuric H 2 SO 4, and hydrochloric HCl.

Oxygen availability distinguish between oxygen-containing acids ( HNO 3, H 3 PO 4 etc.) and anoxic acids ( HCl, H 2 S, HCN, etc.).

By basicity, i.e. according to the number of hydrogen atoms in the acid molecule that can be replaced by metal atoms to form a salt, acids are subdivided into monobasic (for example, HNO 3, HCl), dibasic (H 2 S, H 2 SO 4), tribasic (H 3 PO 4), etc.

The names of anoxic acids are derived from the name of a non-metal with the addition of the ending -hydrogen: HCl - hydrochloric acid, H 2 S e - hydroselenic acid, HCN - hydrocyanic acid.

The names of oxygen-containing acids are also derived from the Russian name of the corresponding element with the addition of the word "acid". In this case, the name of the acid in which the element is in the highest oxidation state ends in "naya" or "new", for example, H 2 SO 4 - sulphuric acid, HClO 4 - perchloric acid, H 3 AsO 4 - arsenic acid. With a decrease in the oxidation state of the acid-forming element, the endings change in the following sequence: "ovate" ( HClO 3 - chloric acid), "true" ( HClO 2 - chloride acid), "ovate" ( H О Cl - hypochlorous acid). If an element forms acids, being in only two oxidation states, then the name of the acid corresponding to the lowest oxidation state of the element receives the ending "true" ( HNO 3 - Nitric acid, HNO 2 - nitrous acid).

Table - The most important acids and their salts

Acid		Corresponding normal salt names
Name	Formula
Nitrogen	HNO 3	Nitrates
Nitrogenous	HNO 2	Nitrite
Borna (orthoboric)	H 3 BO 3	Borates (orthoborates)
Hydrobromic		Bromides
Hydrogen iodide		Iodides
Silicon	H 2 SiO 3	Silicates
Manganese	HMnO 4	Permanganates
Metaphosphoric	HPO 3	Metaphosphates
Arsenic	H 3 AsO 4	Arsenates
Arsenic	H 3 AsO 3	Arsenites
Orthophosphoric	H 3 PO 4	Orthophosphates (phosphates)
Diphosphoric (pyrophosphoric)	H 4 P 2 O 7	Diphosphates (pyrophosphates)
Dichromic	H 2 Cr 2 O 7	Dichromats
Sulfur	H 2 SO 4	Sulphates
Sulphurous	H 2 SO 3	Sulfites
Coal	H 2 CO 3	Carbonates
Phosphorous	H 3 PO 3	Phosphites
Hydrogen fluoride (hydrofluoric)		Fluoride
Hydrochloric (hydrochloric)		Chlorides
Chlorine	HClO 4	Perchlorates
Chloric	HClO 3	Chlorates
Hypochlorous	HClO	Hypochlorites
Chrome	H 2 CrO 4	Chromates
Hydrogen cyanide (cyanide)		Cyanide

Getting acids

1. Anoxic acids can be obtained by direct combination of non-metals with hydrogen:

H 2 + Cl 2 → 2HCl,

H 2 + S H 2 S.

2. Oxygen-containing acids can often be obtained by direct combination of acidic oxides with water:

SO 3 + H 2 O = H 2 SO 4,

CO 2 + H 2 O = H 2 CO 3,

P 2 O 5 + H 2 O = 2 HPO 3.

3. Both anoxic and oxygen-containing acids can be obtained by exchange reactions between salts and other acids:

BaBr 2 + H 2 SO 4 = BaSO 4 + 2HBr,

CuSO 4 + H 2 S = H 2 SO 4 + CuS,

CaCO 3 + 2HBr = CaBr 2 + CO 2 + H 2 O.

4. In some cases, redox reactions can be used to obtain acids:

H 2 O 2 + SO 2 = H 2 SO 4,

3P + 5HNO 3 + 2H 2 O = 3H 3 PO 4 + 5NO.

Chemical properties of acids

1. The most characteristic chemical property of acids is their ability to react with bases (as well as basic and amphoteric oxides) to form salts, for example:

H 2 SO 4 + 2NaOH = Na 2 SO 4 + 2H 2 O,

2HNO 3 + FeO = Fe (NO 3) 2 + H 2 O,

2 HCl + ZnO = ZnCl 2 + H 2 O.

2. The ability to interact with some metals in the voltage range up to hydrogen, with the release of hydrogen:

Zn + 2HCl = ZnCl 2 + H 2,

2Al + 6HCl = 2AlCl 3 + 3H 2.

3.With salts, if a slightly soluble salt or volatile substance is formed:

H 2 SO 4 + BaCl 2 = BaSO 4 ↓ + 2HCl,

2HCl + Na 2 CO 3 = 2NaCl + H 2 O + CO 2,

2KHCO 3 + H 2 SO 4 = K 2 SO 4 + 2SO 2+ 2H 2 O.

Note that polybasic acids dissociate stepwise, and the ease of dissociation in each of the steps decreases, therefore, for polybasic acids, instead of medium salts, acidic ones are often formed (in the case of an excess of the reacting acid):

Na 2 S + H 3 PO 4 = Na 2 HPO 4 + H 2 S,

NaOH + H 3 PO 4 = NaH 2 PO 4 + H 2 O.

4. A particular case of acid-base interaction is the reaction of acids with indicators, leading to a color change, which has long been used for the qualitative detection of acids in solutions. So, litmus changes color in an acidic environment to red.

5. When heated, oxygen-containing acids decompose into oxide and water (preferably in the presence of a dehydrating P 2 O 5):

H 2 SO 4 = H 2 O + SO 3,

H 2 SiO 3 = H 2 O + SiO 2.

M.V. Andryukhova, L.N. Bopodina

Lecture: Characteristic Chemical properties acids

Classificationacids

Acids are such chemical substances, during the electrolytic dissociation of which one or more hydrogen cations H + and an acid residue are formed.

Acidic residue- these are anions formed during the dissociation of acids.

There are several classifications of acids:

1. According to the composition of the acid residue, acids are divided into:

oxygen-free.

Oxygenated acids are hydroxides. They belong to this group, since they contain an OH - group. These include acids:

• sulfuric - H 2 SO 4;
• sulphurous - H 2 SO 3;
• nitrogen - HNO 3;
• phosphoric - H 3 PO 4;
• coal - H 2 CO 3;
• silicon - H 2 SiO 3.

Oxygen-free acids, as the name implies, do not have oxygen in their composition. These include acids:

hydrofluoric HF;

hydrochloric or hydrochloric HCl;

hydrogen bromide HBr;

hydrogen iodide HI;

hydrogen sulfide H2S.

2. By the number of hydrogen atoms in the composition:

• monobasic (HNO 3, HF, etc.),
• dibasic (H 2 SO 4, H 2 CO 3, etc.),
• tribasic (H 3 PO 4).

Chemical properties of acids

1. Many acids dissolve in water, giving it a sour taste. If it is necessary to find out the presence of acid in the solution, indicators are used: litmus and methyl orange turn red.

2. Strong acids interact with alkalis. The neutralization reaction already known to you occurs, due to the fact that the acidic environment of the acid, as well as alkaline environment alkalis together form a neutral water environment. The abbreviated ionic equation of the neutralization reaction has the general form:

H + + OH - → H 2 O

3. Interact with basic and amphoteric bases and oxides to form salts and water. Due to the formation of electrolyte, these reactions always go to the end. Many oxides and insoluble bases dissolve in them.

4. The interaction of acids with salts is possible, provided that poorly soluble or gaseous substances are formed.

Let us turn Special attention on the interaction of acids with metals:

1. Hydrochloric and dilute sulfuric acids interact with metals that are in the electrochemical series up to hydrogen, due to the fact that the oxidizing agent here is the hydrogen cation H +:

Mg + 2HCl → MgCl 2 + H 2;

Mg + H 2 SO 4 (dil.) → MgSO 4 + H 2.

Hydrochloric and dilute sulfuric acids are oxidized to lower degrees metals of variable valence. For example, iron is oxidized to the +2 oxidation state:

Fe + 2HCl → FeCl 2 + H 2.

2. In concentrated sulfuric acid, sulfate serves as an oxidizing agent. In it, sulfur has an oxidation state of +6. When interacting with metals, sulfuric acid is always reduced to hydrogen sulfide (H 2 S), sulfur (S) and sulfur oxide IV (SO 2). The reduction products of the presented acid directly depend on the activity of the reacting metal. In the process of interaction of concentrated sulfuric acid with active metals, salt, water and hydrogen sulfide will be formed. Low-active metals will reduce sulfuric acid to SO 2. And metals of medium activity up to S. Metals of variable valence are capable of oxidizing to concentrated sulfuric acid, which has the highest oxidation state. Noble metals (Au, Pt and some others) do not interact with concentrated sulfuric acid. Some metals (Al, Fe, Cr, Ni) react with concentrated sulfuric acid only when heated, for example, lead, to form a soluble acid salt.

3. In nitric acid, the nitrate ion, containing nitrogen with an oxidation state of +5, serves as an oxidizing agent, so hydrogen is not released, but only reduction products are released nitric acid: NH 4 NO 3, N 2, N 2 O, NO, HNO 2, NO 2. Free ammonia is also not released because it reacts with nitric acid to form ammonium nitrate NH 4 NO 3. In the case of the reaction of metals with concentrated nitric acid, predominantly NO 2 becomes the reduction product, regardless of the nature of the metal. For example, when a piece of copper is dipped into concentrated nitric acid, a brown gas will begin to evolve, and a blue solution of copper (II) nitrate will appear at the bottom. Metals of variable valence in reaction with concentrated nitric acid are oxidized to the highest degree... Metals oxidized to the +4 degree and higher will form acids or oxides. In concentrated nitric acid Al, Fe, Cr, Ni, Co and some other metals are passivated. After treatment with nitric acid, they will stop reacting with other acids.

4. The more active the metal interacting with dilute nitric acid, the more nitric acid is reduced. And the products of the reduction of dilute nitric acid with metals of medium activity are nitrogen or nitric oxide (I). Low-activity metals are reduced from this acid nitric oxide (II). Remember, the higher the activity of the metal and the lower the concentration of nitric acid, the lower the oxidation state of nitrogen in the compound formed more than others. Oxidation of noble metals occurs with the formation of complex acids. Some metals, for example, Nb, Ta, W do not dissolve even in such a solution, but dissolve in a mixture of nitric and hydrofluoric acids:

3Ta + 5HNO 3 + 21HF → 3H 2 TaF 7 + 5NO + 10H 2 O

W + 2HNO 3 + 8HF → H 2 WF 8 + 2NO + 4H 2 O.

Do not underestimate the role of acids in our life, because many of them are simply irreplaceable in Everyday life... First, let's remember what acids are. These are complex substances. The formula is written as follows: HnA, where H is hydrogen, n is the number of atoms, A is the acid residue.

The main properties of acids include the ability to replace molecules of hydrogen atoms with metal atoms. Most of them are not only caustic, but also very poisonous. But there are those that we constantly encounter, without harm to our health: vitamin C, lemon acid, lactic acid. Let's consider the basic properties of acids.

Physical properties

The physical properties of acids often provide a clue to their nature. Acids can exist in three forms: solid, liquid and gaseous. For example: nitric (HNO3) and sulfuric acid (H2SO4) are colorless liquids; boric (H3BO3) and metaphosphoric (HPO3) are solid acids. Some of them have color and smell. Different acids dissolve in water differently. There are also insoluble ones: H2SiO3 - silicon. Liquids taste sour. The name of some acids was given by the fruits in which they are found: malic acid, citric acid. Others get their name from chemical elements contained in them.

Classification of acids

Acids are usually classified according to several criteria. The very first is, according to the oxygen content in them. Namely: oxygen-containing (HClO4 - chloric) and oxygen-free (H2S - hydrogen sulfide).

By the number of hydrogen atoms (by basicity):

• Monobasic - contains one hydrogen atom (HMnO4);
• Dibasic - has two hydrogen atoms (H2CO3);
• Tribasic, respectively, have three hydrogen atoms (H3BO);
• Polybasic - have four or more atoms, are rare (H4P2O7).

By class chemical compounds, are divided into organic and inorganic acids. The former are mainly found in herbal products: acetic, lactic, nicotinic, ascorbic acids. Inorganic acids include: sulfuric, nitric, boric, arsenic. The range of their application is quite wide, from industrial needs (production of dyes, electrolytes, ceramics, fertilizers, etc.) to cooking or cleaning sewers. Acids can also be classified by strength, volatility, stability, and water solubility.

Chemical properties

Let's consider the basic chemical properties of acids.

• The first is interaction with indicators. Litmus, methyl orange, phenolphthalein and universal test paper are used as indicators. In acid solutions, the color of the indicator will change color: litmus and universal ind. paper will turn red, methyl orange will turn pink, phenolphthalein will remain colorless.
• The second is the interaction of acids with bases. This reaction is also called neutralization. The acid reacts with the base, resulting in salt + water. For example: H2SO4 + Ca (OH) 2 = CaSO4 + 2 H2O.
• Since almost all acids are readily soluble in water, neutralization can be carried out with both soluble and insoluble bases. An exception is silicic acid, it is almost insoluble in water. To neutralize it, bases such as KOH or NaOH are required (they are soluble in water).
• The third is the interaction of acids with basic oxides. Here the neutralization reaction also takes place. Basic oxides are close relatives of bases, therefore, the reaction is the same. We use these oxidizing properties of acids very often. For example, to remove rust from pipes. The acid reacts with the oxide to form a soluble salt.
• The fourth is the reaction with metals. Not all metals react equally well with acids. They are divided into active (K, Ba, Ca, Na, Mg, Al, Mn, Zn, Cr, Fe, Ni, Sn. Pb) and inactive (Cu, Hg, Ag, Pt, Au). It is also worth paying attention to the strength of the acid (strong, weak). For example, hydrochloric and sulfuric acids are capable of reacting with all inactive metals, while citric and oxalic acids are so weak that they react very slowly even with active metals.
• The fifth is the reaction of oxygen-containing acids to heating. Almost all acids of this group, when heated, decompose into oxygen oxide and water. The exceptions are carbonic (H3PO4) and sulfurous acids (H2SO4). When heated, they decompose into water and gas. This must be remembered. These are all the basic properties of acids.

Modern chemical science represents many different branches, and each of them, in addition to the theoretical basis, has great applied value, practical. Whatever you touch, everything around is chemical products. The main sections are inorganic and organic chemistry... Let us consider which main classes of substances are classified as inorganic and what properties they possess.

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 compounds of inorganic nature 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 receiving, 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. Interactions describing chemical properties are also shown. However, we will look at each of the classes separately and in more detail.

Group of compounds - oxides

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

Me + n O + C = Me 0 + CO

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

KO + water = acid

2. Reactions with bases:

CO 2 + 2CsOH = Cs 2 CO 3 + H 2 O

3. Reactions with basic oxides: salt formation

P 2 O 5 + 3MnO = Mn 3 (PO 3) 2

4. OVR reactions:

CO 2 + 2Ca = C + 2CaO,

They exhibit 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 = salt + H 2 O

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

Al 2 O 3 + LiOH + water = Li

3. Reactions with acid oxides: obtaining salts

FeO + SO 2 = FeSO 3

4. Reactions with RO: salt formation, fusion

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

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

Al 2 O 3 + 2LiOH = 2LiAlO 2 + H 2 O

They form neither acids nor alkalis. Show narrowly specific properties.

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

Organic and inorganic acids

In the classical sound (based on the positions of ED - electrolytic dissociation - acids are compounds, in aquatic environment dissociating into H + cations and anions of acid residues An -. However, acids have been studied extensively in anhydrous conditions today, so there are many different theories for hydroxides.

Empirical formulas of oxides, bases, acids, salts are composed only of symbols, elements and indices indicating their amount in a substance. For example, inorganic acids are expressed by the formula H + acidic residue n-. Organic matter have a different theoretical mapping. In addition to the empirical one, a complete and abbreviated structural formula can be written for them, which will reflect not only the composition and quantity of the molecule, but also the order of arrangement of atoms, their relationship with each other and the main functional group for carboxylic acids --COOH.

In inorganic, all acids are divided into two groups:

• oxygen-free - 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). In terms of strength, acids can be strong: sulfuric, hydrochloric, nitric, chloric and others, as well as weak: hydrogen sulfide, hypochlorous and others.

Organic chemistry offers less variety. Acids that are organic in nature are carboxylic acids. Their common feature- the presence of a functional group -COOH. For example, HCOOH (formic), CH 3 COOH (acetic), C 17 H 35 COOH (stearic) and others.

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

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

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

Properties of inorganic acids

The main physical properties must be attributed, first of all, to a different state of aggregation. After all, there are a number of acids in the form of crystals or powders (boric, orthophosphoric) at normal conditions... The overwhelming majority of the well-known inorganic acids are different liquids. Boiling and melting points also vary.

Acids can cause severe burns, as they have a force that destroys organic tissue and skin. Indicators are used to detect acids:

• methyl orange (in a 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.

Chemical properties of inorganic acids

What they interact with	Example reaction
1. With simple substances, metals. A prerequisite: the metal must stand in the EHRNM before hydrogen, since the metals that stand after hydrogen are not able to displace it from the composition of acids. The reaction always produces hydrogen gas and salt.
2. With bases. The result of the reaction is salt and water. Such reactions of strong acids with alkalis are called neutralization reactions.	Any acid (strong) + soluble base = salt and water
3. With amphoteric hydroxides. Bottom line: salt and water.	2HNO 2 + beryllium hydroxide = Be (NO 2) 2 (average salt) + 2H 2 O
4. With basic oxides. Bottom line: water, salt.	2HCL + FeO = iron (II) chloride + H 2 O
5. With amphoteric oxides. The net effect is salt and water.	2HI + ZnO = ZnI 2 + H 2 O
6. With salts formed by weaker acids. The net effect is salt and weak acid.	2HBr + MgCO 3 = magnesium bromide + H 2 O + CO 2

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 are considered when interacting with metals.

Hydroxides: alkalis, amphoteric and insoluble bases

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

Just like acids, according to the theory of ED, bases are called substances that are capable of aqueous solution decompose into metal cations Ме n + and anions of hydroxo groups ОН -.

• Soluble or alkalis (strong bases that change. Formed by metals of groups I, II. Example: KOH, NaOH, LiOH (that is, only the elements of the main subgroups are taken into account);
• Slightly soluble or insoluble (medium strength, do not change the color of indicators). Example: hydroxide of magnesium, iron (II), (III) and others.
• Molecular (weak bases, in an aqueous medium 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. Grade 8-9 chemistry involves a detailed study of alkalis and poorly soluble compounds.

The main characteristic properties of the bases

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

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

The chemical properties of each group of bases are different.

Chemical properties
Alkalis	Slightly soluble bases	Amphoteric hydroxides
I. Interact with KO (total - salt and water): 2LiOH + SO 3 = Li 2 SO 4 + water II. Interact with acids (salt and water): normal neutralization reactions (see acids) III. They interact with AO to form a hydroxo complex of salt and water: 2NaOH + Me + n O = Na 2 Me + n O 2 + H 2 O, or Na 2 IV. Interact with amphoteric hydroxides to form hydroxocomplex salts: The same as with AO, only without water V. Interact with soluble salts to form insoluble hydroxides and salts: 3CsOH + iron (III) chloride = Fe (OH) 3 + 3CsCl Vi. React with zinc and aluminum in aqueous solution to form salts and hydrogen: 2RbOH + 2Al + water = complex with hydroxide ion 2Rb + 3H 2	I. When heated, they can decompose: insoluble hydroxide = oxide + water II. Reactions with acids (total: salt and water): Fe (OH) 2 + 2HBr = FeBr 2 + water III. Interact with KO: Me + n (OH) n + KO = salt + H 2 O	I. React with acids to form salt and water: (II) + 2HBr = CuBr 2 + water II. Reacts with alkalis: total salt and water (condition: fusion) Zn (OH) 2 + 2CsOH = salt + 2H 2 O III. They react with strong hydroxides: the result is salts, if the reaction proceeds in an aqueous solution: Cr (OH) 3 + 3RbOH = Rb 3

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

Class of inorganic salts. Classification, physical properties

Based on the position of ED, salts can be called inorganic compounds that dissociate in an aqueous solution into metal cations Ме + n and anions of acid residues An n-. This is how salts can be imagined. The definition of chemistry gives more than one, but it is the most accurate.

Moreover, by their chemical nature, all salts are subdivided into:

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

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

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

If we talk about the state of aggregation of salts, then one should notice their uniformity. They exist only in solid, crystalline or powdery state. The color scheme is quite diverse. 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 base, acid, salt. 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 other soluble salt to form insoluble salt and soluble:

PbCL 2 + Na 2 S = PbS + 2NaCL

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

Mg + 2AgCL = MgCL 2 + 2Ag

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

Formulas of oxides, bases, acids, salts reflect the chemical essence 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, you should pay special attention to their writing. A huge variety of compounds offers us in general amazing science- chemistry. Oxides, bases, acids, salts are just a part of the immense variety.