Oxides are complex substances consisting of two elements, of which one is oxygen in the second oxidation state.
In the chemical literature for the nomenclature of oxides adhere to the following rules:
Oxides can be obtained in several different ways:
Classification of oxides based on their chemicalproperties implies their division into salt-forming and non-salt-forming oxides (indifferent). Salt-forming oxides, in turn, are divided into acidic, basic and amphoteric.
The basic oxides correspond to the grounds. For example, Na₂O, CaO, MgO are basic oxides, since they correspond to the bases - NaOH, Ca (OH) ₂, Mg (OH) ₂. Some oxides (K₂O and CaO) easily react with water and form the corresponding bases:
CaO + H₂O = Ca (OH) ₂
K₂O + H₂O = 2KOH
Oxides Fe₂O₃, CuO, Ag₂O do not react with water, but neutralize acids, due to which they are considered as the main:
Fe₂O₃, + 6HCl = 2FeCl₃ + 3H₂OCuO + H₂SO₄ + H₂O
Ag₂O + 2HNO₃ = 2AgNO₃ + H₂O
Typical chemical properties of oxides of this type are their reaction with acids, as a result of which, as a rule, water and salt are formed:
FeO + 2HCl = FeCl₂ + H₂O
The basic oxides also react with acidic oxides:
CaO + CO₂ = CaCO₃.
Acidic oxides correspond to acids. For example, N₂O окси oxide corresponds to nitric acid HNO₂, Cl₂O₇ - perchloric acid HClO₄, SO₃ - sulfuric acid H₂SO₄.
The main chemical property of such oxides is their reaction with bases, salt and water are formed:
2NaOH + CO₂ = NaCO₃ + H₂O
Most acidic oxides reactwith water, forming the corresponding acids. At the same time, SiO окси oxide is practically insoluble in water, however it neutralizes the bases, therefore, it is an acid oxide:
2NaOH + SiO₂ = (fusion) Na₂siO₃ + H₂O
Amphoteric oxides Are oxides, which, depending on the conditionsshow acidic and basic properties, i.e. when interacting with acids, behave like basic oxides, and when interacting with bases they behave like acid oxides.
Not all amphoteric oxides interact to the same degree with bases and acids. Some have more basic properties, others have acidic properties.
If zinc oxide or chromium reacts to the same degree with acids and bases, then the basic properties of Fe₂O окси oxide predominate.
The properties of amphoteric oxides are illustrated by the example of ZnO:
ZnO + 2HCl = ZnCl₂ + H₂O
ZnO + 2NaOH = Na₂ZnO₂ + H₂O
Non-forming oxides do not form acids or bases (for example, N₂O, NO).
In addition, they do not give the reactions characteristic ofsalt-forming oxides. Non-forming oxides can react with acids or alkalis, but no products characteristic of salt-forming oxides are formed, for example, at 150 ° C and 1.5 MPa, CO reacts with sodium hydroxide to form sodium formate:
CO + NaOH = HCOONa
Nonsolidogenic oxides are not as widely distributed as other types of oxides and are formed, mainly, with the participation of divalent non-metals.
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