Oxides are basic acidic amphoteric. What are oxides

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. Salts.
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 in mandatory, in grades 8-11.

Exists general table oxides, salts, bases, acids, which presents examples of each of the substances and their state of aggregation, being in nature. And also shows interactions describing Chemical properties... 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 - Svante Arrhenius), 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 substances have a different theoretical display. 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

To the main physical properties must be attributed primarily to a different state of aggregation. After all, there are a number of acids in the form of crystals or powders (boric, orthophosphoric) under normal conditions. The overwhelming majority of the 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. Required condition: 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, explained by the structure of the 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.

As well as acids, according to the theory of ED, bases are called substances that can decompose in an aqueous solution into metal cations Ме n + and anions of hydroxo groups ОН -.

• Soluble or alkaline (strong bases that change the color of indicators). 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 the alkali is white, then the 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 quite simple and obeys the general laws 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 is offered to us as a whole by an amazing science - chemistry. Oxides, bases, acids, salts are just a part of the immense variety.

Oxides are complex substances consisting of two elements, one of which is oxygen. In the names of oxides, the word oxide is first indicated, then the name of the second element by which it is formed. What are the features of acidic oxides, and how do they differ from other types of oxides?

Classification of oxides

Oxides are divided into salt-forming and non-salt-forming. Already from the name it is clear that non-salt-forming ones do not form salts. There are few such oxides: this is water H 2 O, oxygen fluoride OF 2 (if it is conventionally considered an oxide), carbon monoxide, or carbon monoxide (II), carbon monoxide CO; nitrogen oxides (I) and (II): N 2 O (dinitrogen oxide, laughing gas) and NO (nitrogen monoxide).

Salt-forming oxides form salts when interacting with acids or alkalis. Bases, amphoteric bases and oxygen-containing acids correspond to them as hydroxides. Accordingly, they are called basic oxides (eg CaO), amphoteric oxides (Al 2 O 3) and acid oxides or acid anhydrides (CO 2).

Rice. 1. Types of oxides.

Often, students are faced with the question of how to distinguish a basic oxide from an acidic one. First of all, you need to pay attention to the second element next to oxygen. Acid oxides - contain a non-metal or a transition metal (CO 2, SO 3, P 2 O 5); basic oxides - contain a metal (Na 2 O, FeO, CuO).

Basic properties of acidic oxides

Acidic oxides (anhydrides) are substances that exhibit acidic properties and form oxygenated acids. Therefore, acidic oxides correspond to acids. For example, acidic oxides SO 2, SO 3 correspond to the acids H 2 SO 3 and H 2 SO 4.

Rice. 2. Acidic oxides with corresponding acids.

Acidic oxides formed by non-metals and metals with variable valence in the highest oxidation state (for example, SO 3, Mn 2 O 7) react with basic oxides and alkalis to form salts:

SO 3 (acidic oxide) + CaO (basic oxide) = CaSO 4 (salt);

Typical reactions are the interaction of acidic oxides with bases, resulting in the formation of salt and water:

Mn 2 O 7 (acidic oxide) + 2KOH (alkali) = 2KMnO 4 (salt) + H 2 O (water)

All acidic oxides, except for silicon dioxide SiO 2 (silicic anhydride, silica), react with water, forming acids:

SO 3 (acidic oxide) + H 2 O (water) = H 2 SO 4 (acid)

Acidic oxides are formed by interaction with oxygen of simple and complex substances (S + O 2 = SO 2), or by decomposition as a result of heating complex substances containing oxygen - acids, insoluble bases, salts (H 2 SiO 3 = SiO 2 + H 2 O).

List of acidic oxides:

Acid Oxide Name	Acid Oxide Formula	Acid Oxide Properties
Sulfur (IV) oxide	SO 2	colorless toxic gas with a pungent odor
Sulfur (VI) oxide	SO 3	highly volatile colorless toxic liquid
Carbon monoxide (IV)	CO 2	colorless, odorless gas
Silicon (IV) oxide	SiO 2	colorless crystals with strength
Phosphorus (V) oxide	P 2 O 5	white flammable powder with unpleasant odor
Nitric oxide (V)	N 2 O 5	substance composed of colorless volatile crystals
Chlorine (VII) oxide	Cl 2 O 7	colorless oily toxic liquid
Manganese (VII) oxide	Mn 2 O 7	liquid with a metallic luster, which is a strong oxidizing agent.

Today we begin our acquaintance with the most important classes of inorganic compounds. Inorganic substances are divided according to their composition, as you already know, into simple and complex ones.

OXIDE	ACID	BASE	SALT
E x O y	HnA A - acid residue	Me (OH)b OH - hydroxyl group	Me n A b

Complex inorganic substances are divided into four classes: oxides, acids, bases, salts. We start with the oxide class.

OXIDES

Oxides are complex substances, consisting of two chemical elements, one of which is oxygen, with a valency equal to 2. Only one chemical element - fluorine, combining with oxygen, forms not an oxide, but oxygen fluoride OF 2.
They are called simply - "oxide + element name" (see table). If the valence chemical element variable, then it is indicated by a Roman numeral, enclosed in parentheses, after the name of the chemical element.

Formula	Name	Formula	Name
	carbon monoxide (II)	Fe 2 O 3	iron (III) oxide
	nitric oxide (II)	CrO 3	chromium (VI) oxide
Al 2 O 3	aluminium oxide		zinc oxide
N 2 O 5	nitric oxide (V)	Mn 2 O 7	manganese (VII) oxide

Classification of oxides

All oxides can be divided into two groups: salt-forming (basic, acidic, amphoteric) and non-salt-forming or indifferent.

Metal oxides Me x O y			Nonmetal oxides notMe x O y
The main	Acidic	Amphoteric	Acidic	Indifferent
I, II Me	V-VII Me	ZnO, BeO, Al 2 O 3, Fe 2 O 3, Cr 2 O 3	> II not me	I, II not me CO, NO, N 2 O

1). Basic oxides Are the oxides to which the bases correspond. Basic oxides include oxides metals 1 and 2 groups, as well metals side subgroups with valence I and II (except for ZnO - zinc oxide and BeO - beryllium oxide):

2). Acidic oxides Are the oxides to which acids correspond. Acidic oxides include nonmetal oxides (except for non-salt-forming - indifferent), as well as metal oxides side subgroups with a valence of V before Vii (For example, CrO 3 is chromium (VI) oxide, Mn 2 O 7 is manganese (VII) oxide):

3). Amphoteric oxides- these are oxides, which correspond to bases and acids. These include metal oxides major and minor subgroups with valence III , sometimes IV as well as zinc and beryllium (For example, BeO, ZnO, Al 2 O 3, Cr 2 O 3).

4). Non-salt-forming oxides- these are oxides that are indifferent to acids and bases. These include nonmetal oxides with valence I and II (For example, N 2 O, NO, CO).

Conclusion: the nature of the properties of oxides primarily depends on the valence of the element.

For example, chromium oxides:

CrO (II- main);

Cr 2 O 3 (III- amphoteric);

CrO 3 (Vii- acidic).

Classification of oxides

(by solubility in water)

Acidic oxides	Basic oxides	Amphoteric oxides
Soluble in water. Exception - SiO 2 (insoluble in water)	Only oxides of alkali and alkaline earth metals dissolve in water (these are metals I "A" and II "A" groups, exclusion Be, Mg)	They do not interact with water. Insoluble in water

Complete tasks:

1. Write down separately chemical formulas salt-forming acid and basic oxides.

NaOH, AlCl 3, K 2 O, H 2 SO 4, SO 3, P 2 O 5, HNO 3, CaO, CO.

2. Given substances : CaO, NaOH, CO 2, H 2 SO 3, CaCl 2, FeCl 3, Zn (OH) 2, N 2 O 5, Al 2 O 3, Ca (OH) 2, CO 2, N 2 O, FeO, SO 3, Na 2 SO 4, ZnO, CaCO 3, Mn 2 O 7, CuO, KOH, CO, Fe (OH) 3

Write down the oxides and classify them.

Obtaining oxides

Simulator "Interaction of oxygen with simple substances"

1. Combustion of substances (Oxidation with oxygen)	a) simple substances Training apparatus	2Mg + O 2 = 2MgO
	b) complex substances	2H 2 S + 3O 2 = 2H 2 O + 2SO 2
2.Decomposition of complex substances (use acid table, see appendices)	a) salts SALTt= BASIC OXIDE + ACID OXIDE	СaCO 3 = CaO + CO 2
	b) Insoluble bases Me (OH)bt= Me x O y+ H 2 O	Cu (OH) 2 t = CuO + H 2 O
	c) oxygenated acids HnA =ACID OXIDE + H 2 O	H 2 SO 3 = H 2 O + SO 2

Physical properties of oxides

At room temperature most oxides are solids (CaO, Fe 2 O 3, etc.), some are liquids (H 2 O, Cl 2 O 7, etc.) and gases (NO, SO 2, etc.).

Chemical properties of oxides

CHEMICAL PROPERTIES OF BASIC OXIDES 1. Basic oxide + Acidic oxide = Salt (p. Compound) CaO + SO 2 = CaSO 3 2. Basic oxide + Acid = Salt + H 2 O (p. Exchange) 3 K 2 O + 2 H 3 PO 4 = 2 K 3 PO 4 + 3 H 2 O 3. Basic oxide + Water = Alkali (p. Compound) Na 2 O + H 2 O = 2 NaOH

CHEMICAL PROPERTIES OF ACID OXIDES 1. Acid oxide + Water = Acid (p. Compound) C O 2 + H 2 O = H 2 CO 3, SiO 2 - does not react 2. Acid oxide + Base = Salt + H 2 O (p. Exchange) P 2 O 5 + 6 KOH = 2 K 3 PO 4 + 3 H 2 O 3. Basic oxide + Acidic oxide = Salt (p. Compound) CaO + SO 2 = CaSO 3 4. The less volatile displace the more volatile ones from their salts CaCO 3 + SiO 2 = CaSiO 3 + CO 2

CHEMICAL PROPERTIES OF AMPHOTHERIC OXIDES They interact with both acids and alkalis. ZnO + 2 HCl = ZnCl 2 + H 2 O ZnO + 2 NaOH + H 2 O = Na 2 [Zn (OH) 4] (in solution) ZnO + 2 NaOH = Na 2 ZnO 2 + H 2 O (when fusion)

Application of oxides

Some oxides do not dissolve in water, but many enter into a compound reaction with water:

SO 3 + H 2 O = H 2 SO 4

CaO + H 2 O = Ca( OH) 2

The result is often highly desirable and useful compounds. For example, H 2 SO 4 is sulfuric acid, Ca (OH) 2 is slaked lime, etc.

If oxides are insoluble in water, then people skillfully use this property as well. For example, zinc oxide ZnO is a white substance, therefore it is used to prepare white oil paint(zinc white). Since ZnO is practically insoluble in water, zinc white can be used to paint any surfaces, including those that are exposed to atmospheric precipitation. Insolubility and non-toxicity make it possible to use this oxide in the manufacture of cosmetic creams and powders. Pharmacists make it an astringent and drying powder for external use.

Titanium (IV) oxide - TiO 2 has the same valuable properties. He also has a handsome White color and is used for the manufacture of titanium white. TiO 2 does not dissolve not only in water, but also in acids; therefore, coatings made of this oxide are especially resistant. This oxide is added to the plastic to give it a white color. It is part of enamels for metal and ceramic dishes.

Chromium (III) oxide - Cr 2 O 3 - very strong crystals of dark green color, insoluble in water. Cr 2 O 3 is used as a pigment (paint) in the manufacture of decorative green glass and ceramics. The GOI paste known to many (abbreviated from the name "State Optical Institute") is used for grinding and polishing optics, metal products, in jewelry.

Due to the insolubility and strength of chromium (III) oxide, it is also used in printing inks (for example, for coloring banknotes). In general, oxides of many metals are used as pigments for a wide variety of paints, although this is far from their only application.

Tasks for consolidation

1. Write down separately the chemical formulas of salt-forming acid and basic oxides.

NaOH, AlCl 3, K 2 O, H 2 SO 4, SO 3, P 2 O 5, HNO 3, CaO, CO.

2. Given substances : CaO, NaOH, CO 2, H 2 SO 3, CaCl 2, FeCl 3, Zn (OH) 2, N 2 O 5, Al 2 O 3, Ca (OH) 2, CO 2, N 2 O, FeO, SO 3, Na 2 SO 4, ZnO, CaCO 3, Mn 2 O 7, CuO, KOH, CO, Fe (OH) 3

Choose from the list: basic oxides, acidic oxides, indifferent oxides, amphoteric oxides and give them names.

3. Finish CCM, indicate the type of reaction, name the reaction products

Na 2 O + H 2 O =

N 2 O 5 + H 2 O =

CaO + HNO 3 =

NaOH + P 2 O 5 =

K 2 O + CO 2 =

Cu (OH) 2 =? +?

4. Carry out the transformations according to the scheme:

1) K → K 2 O → KOH → K 2 SO 4

2) S → SO 2 → H 2 SO 3 → Na 2 SO 3

3) P → P 2 O 5 → H 3 PO 4 → K 3 PO 4

All chemical compounds that exist in nature are divided into organic and inorganic. Among the latter, the following classes are distinguished: oxides, hydroxides, salts. Hydroxides are classified into bases, acids, and amphoteric. Among the oxides, acidic, basic and amphoteric can also be distinguished. Substances of the latter group can exhibit both acidic and basic properties.

Chemical properties of acidic oxides

Such substances have peculiar chemical properties. Acidic oxides are capable of entering into chemical reactions only with basic hydroxides and oxides. This group of chemical compounds includes such substances as carbon dioxide, sulfur dioxide and trioxide, chromium trioxide, manganese heptaoxide, phosphorus pentoxide, chlorine trioxide and pentoxide, nitrogen tetra- and pentoxide, silicon dioxide.

Substances of this kind are also called anhydrides. The acidic properties of oxides are manifested primarily during their reactions with water. This produces a certain oxygen-containing acid. For example, if we take sulfur trioxide and water in equal amounts, we get sulfate (sulfuric) acid. Phosphoric acid can be synthesized in the same way by adding water to phosphorus oxide. Reaction equation: P2O5 + 3H2O = 2H3PO4. In exactly the same way, it is possible to obtain acids such as nitrate, silicic, etc. Also acidic oxides enter into chemical interaction with basic or amphoteric hydroxides. During these reactions, salt and water are formed. For example, if you take sulfur trioxide and add calcium hydroxide to it, you get calcium sulfate and water. If we add zinc hydroxide, we get zinc sulfate and water. Another group of substances with which these chemical compounds interact are basic and amphoteric oxides. When reacting with them, only salt is formed, without water. For example, adding amphoteric alumina to sulfur trioxide, we get aluminum sulfate. And if you mix silicon oxide with basic calcium oxide, you get calcium silicate. In addition, acidic oxides react with basic and normal salts. When reacting with the latter, acidic salts are formed. For example, if you add calcium carbonate and water to carbon dioxide, you can get calcium bicarbonate. Reaction equation: CO 2 + CaCO 3 + H 2 O = Ca (HCO 3) 2. When acid oxides react with basic salts, normal salts are formed.

Substances of this group do not interact with acids and other acidic oxides. Amphoteric oxides can exhibit exactly the same chemical properties, except that they also interact with acid oxides and hydroxides, that is, they combine both acidic and basic properties.

Physical properties and applications of acidic oxides

There are quite a few acidic oxides that differ in their physical properties, so it is possible to use them in the most different areas industry.

Sulfur trioxide

Most often, this compound is used in the chemical industry. It is an intermediate product formed during the production of sulfate acid. This process consists in the fact that iron pyrite is burned, thus obtaining sulfur dioxide, then the latter is subjected to a chemical reaction with oxygen, as a result of which trioxide is formed. Further, sulfuric acid is synthesized from the trioxide by adding water to it. Under normal conditions, this substance is a colorless liquid with an unpleasant odor. At temperatures below sixteen degrees Celsius, sulfur trioxide solidifies, forming crystals.

Phosphorus pentoxide

Acidic oxides also include phosphorus pentoxide. It is a white snow-like substance. It is used as a dehydrating agent due to the fact that it very actively interacts with water, while forming phosphoric acid (it is also used in chemical industry to get it).

Carbon dioxide

It is the most abundant acid oxide in nature. The content of this gas in the composition of the Earth's atmosphere is about one percent. Under normal conditions, this substance is a colorless and odorless gas. Carbon dioxide is widely used in Food Industry: for the production of carbonated drinks, as a baking powder, as a preservative (under the designation E290). Liquefied carbon dioxide is used to make fire extinguishers. Also, this substance plays a huge role in nature - for photosynthesis, as a result of which oxygen, vital for animals, is formed. Plants need exactly carbon dioxide. This substance is released during the combustion of all organic chemical compounds without exception.

Silica

Under normal conditions, it appears as colorless crystals. In nature, it can be found in the form of many different minerals such as quartz, crystal, chalcedony, jasper, topaz, amethyst, morion. This acidic oxide is actively used in the production of ceramics, glass, abrasive materials, concrete products, fiber-optic cables. Also, this substance is used in radio engineering. In the food industry, it is used in the form of an additive encrypted under the name E551. Here it is used to maintain the original shape and consistency of the product. This food additive can be found, for example, in instant coffee. In addition, silicon dioxide is used in the manufacture of toothpastes.

Manganese heptaoxide

This substance is a brownish-green mass. It is used mainly for the synthesis of manganic acid by adding water to the oxide.

Nitrogen Pentoxide

It is a solid, colorless substance in the form of crystals. It is used in most cases in the chemical industry to obtain nitric acid or other nitrogen oxides.

Chlorine trioxide and tetroxide

The first is a green-yellow gas, the second is a liquid of the same color. They are used mainly in the chemical industry to obtain the corresponding chlorous acids.

Getting acidic oxides

Substances of this group can be obtained due to the decomposition of acids under the influence of high temperatures. In this case, the desired substance and water are formed. Examples of reactions: H 2 CO 3 = H 2 O + CO 2; 2H 3 PO 4 = 3H 2 O + P 2 O 5. Manganese heptaoxide can be obtained by exposing potassium permanganate to a concentrated sulfate acid solution. This reaction produces the desired substance, potassium sulfate and water. Carbon dioxide can be obtained through the decomposition of a carboxylic acid, the interaction of carbonates and bicarbonates with acids, reactions baking soda with citric acid.

Conclusion

Summing up everything written above, we can say that acid oxides are widely used in the chemical industry. Few of them are also used in food and other industries.

Acidic oxides are a large group of inorganic chemical compounds that are of great importance and can be used to obtain a wide variety of oxygenated acids. This group also includes two important substances: carbon dioxide and silicon dioxide, the first of which plays a huge role in nature, and the second is presented in the form of many minerals that are often used in the manufacture of jewelry.

Oxides are complex substances composed of two elements, one of which is oxygen. Oxides can be salt-forming and non-salt-forming: one of the types of salt-forming oxides are basic oxides. How are they different from other species, and what are their chemical properties?

Salt-forming oxides are classified into basic, acidic, and amphoteric oxides. If bases correspond to basic oxides, acids correspond to acidic oxides, and amphoteric formations correspond to amphoteric oxides. Amphoteric oxides are those compounds that, depending on the conditions, can exhibit either basic or acidic properties.

Rice. 1. Classification of oxides.

The physical properties of oxides are very diverse. They can be both gases (CO 2) and solids (Fe 2 O 3) or liquid substances (H 2 O).

Moreover, most of the basic oxides are solids of various colors.

oxides in which the elements show their highest activity are called higher oxides. The order of increase in the acidic properties of the higher oxides of the corresponding elements in the periods from left to right is explained by the gradual increase in the positive charge of the ions of these elements.

Chemical properties of basic oxides

Basic oxides are the oxides to which the bases correspond. For example, the basic oxides K 2 O, CaO correspond to the bases KOH, Ca (OH) 2.

Rice. 2. Basic oxides and their corresponding bases.

Basic oxides are formed by typical metals, as well as metals of variable valence in the lowest oxidation state (for example, CaO, FeO), react with acids and acid oxides, forming salts:

CaO (basic oxide) + CO 2 (acidic oxide) = CaCO 3 (salt)

FeO (basic oxide) + H 2 SO 4 (acid) = FeSO 4 (salt) + 2H 2 O (water)

Basic oxides also interact with amphoteric oxides, resulting in salt formation, for example:

Only oxides of alkali and alkaline earth metals react with water:

BaO (basic oxide) + H 2 O (water) = Ba (OH) 2 (alkaline earth metal base)

Many basic oxides tend to be reduced to substances consisting of atoms of one chemical element:

3CuO + 2NH 3 = 3Cu + 3H 2 O + N 2

When heated, only mercury and noble metal oxides decompose:

Rice. 3. Mercury oxide.

List of basic oxides:

Oxide name	Chemical formula	Properties
Calcium oxide	CaO	quicklime, white crystalline substance
Magnesium oxide	MgO	white matter, slightly soluble in water
Barium oxide	BaO	colorless crystals with a cubic lattice
Copper oxide II	CuO	black substance practically insoluble in water
	HgO	red or yellow-orange solid
Potassium oxide	K 2 O	colorless or pale yellow substance
Sodium oxide	Na 2 O	substance composed of colorless crystals
Lithium oxide	Li 2 O	substance consisting of colorless crystals that have a cubic lattice structure