Basic oxides and their properties

Oxides are substances in which the molecules consist of an oxygen atom with an oxidation state of 2 and atoms of a second element.

Oxides are formed in a direct way by the interaction of oxygen with another substance or indirectly by decomposition of bases, salts, acids. This type of compound is very common in nature, and can exist as a gas, liquid or solid. In the earth's crust there are also oxides. So, sand, rust, carbon dioxide and even habitual water are all examples of oxides.

There are both salt-forming and non-salt-forming oxides. Salts as a result of chemical reaction give salts. These include oxides of nonmetals and metals that react with water to form acids, and in reaction with the base, salts, normal and acidic. Salts include, for example, copper oxide.

Accordingly, it is impossible to obtain salt from the non-salt-forming ones. Examples include carbon dioxide, dinitrogen oxide and nitric oxide.

The salt-forming oxides are divided into basic, acidic and amphoteric oxides. Let's talk more about the main ones.

So, the basic oxides are oxides of some metals, corresponding to which the hydroxides belong to the class of bases. That is, when interacting with an acid, such substances form water and salt. For example, this is K2O, CaO, MgO, etc. Under normal conditions, the basic oxides are solid crystalline formations. The degree of oxidation of metals in such compounds, as a rule, does not exceed +2 or rarely +3.

Chemical properties of basic oxides

1. Reaction with acid

It is in the reaction with the acid that the oxide exhibits its basic properties; therefore, by such an experiment it is possible to prove the type of one or the other oxide. If salt and water are formed, then this is the main oxide. Acidic oxides in such an interaction form an acid. And amphoteric can exhibit either acidic or basic properties - it depends on the conditions. These are the main differences between the non-salt-forming oxides among themselves.

2. Reaction with water

In the interaction with water, those oxides come into being, which are formed by metals from the electrical voltage range facing magnesium. When reacted with water, they form soluble bases. This group of oxides of alkaline earth and alkali metals (barium oxide, lithium oxide, etc.). Acidic oxides in water form acid, and amphoteric oxides do not react to water.

3. Reaction with amphoteric and acidic oxides

The opposite oxides react chemically, reacting with one another, forming salts. For example, basic oxides can interact with acidic ones, but do not react to other representatives of their group. The most active are oxides of alkali metals, alkaline earth metals and magnesium. Even under normal conditions, they are fused with solid amphoteric oxides, with solid and gaseous acid. When reacting with acidic oxides, they form the corresponding salts.

But the basic oxides of other metals are less active and practically do not react with oxides with gaseous (acidic) ones. They can only enter the addition reaction by fusion with solid acidic oxides.

4. Oxidation-reduction properties

Oxides of active alkali metals do not show significant reducing or oxidizing properties. And, on the contrary, oxides of less active metals can be reduced by coal, hydrogen, ammonia or carbon monoxide.

Obtaining basic oxides

1. Decomposition of hydroxides: when heated, insoluble bases decompose into water and basic oxide.

2. Oxidation of metals: an alkali metal forms a peroxide during combustion in oxygen, which then forms a basic oxide upon reduction.