The substances that form the basis of our physical world are composed of different types of chemical elements. Four of them are the most common. These are hydrogen, carbon, nitrogen and oxygen. The last element can bind with particles of metals or non-metals and form binary compounds - oxides. In our article, we will study the most important methods for obtaining oxides in the laboratory and industry. Also consider their basic physical and chemical properties.
Aggregate state
Oxides, or oxides, exist in three states: gaseous, liquid and solid. For example, the first group includes such well-known and widespread compounds in nature as carbon dioxide - CO2, carbon monoxide - CO, sulfur dioxide - SO2and others. In the liquid phase, there are such oxides as water - H2O, sulfuric anhydride - SO3, nitric oxide - N2 O3. ReceiptThe oxides we have named can be made in the laboratory, but carbon monoxide and sulfur trioxide are also produced commercially. This is due to the use of these compounds in the technological cycles of iron smelting and sulfate acid production. Carbon monoxide is used to reduce iron from ore, and sulfuric anhydride is dissolved in sulfate acid and oleum is mined.
Classification of oxides
There are several types of oxygen-containing substances, consisting of two elements. The chemical properties and methods for obtaining oxides will depend on which of the listed groups the substance belongs to. For example, carbon dioxide, which is an acidic oxide, is obtained by direct combination of carbon with oxygen, carrying out a hard oxidation reaction. Carbon dioxide can also be released during the exchange of s alts of carbonic acid and strong inorganic acids:
HCl + Na2CO3=2NaCl + H2O + CO 2
What kind of reaction is the hallmark of acid oxides? This is their interaction with alkalis:
SO2 + 2NaOH → Na2SO3 + H 2O
Amphoteric and non-s alt-forming oxides
Indifferent oxides, such as CO or N2O, are not capable of reactions leading to the formation of s alts. On the other hand, most acidic oxides can react with water to form acids. However, this is not possible for silicon oxide. It is expedient to obtain silicate acid indirectly.way: from silicates reacting with strong acids. Amphoteric will be such binary compounds with oxygen that are capable of reactions with both alkalis and acids. We will include the following compounds in this group - these are the known oxides of aluminum and zinc.
Obtaining sulfur oxides
In its compounds with oxygen, sulfur exhibits different valencies. So, in sulfur dioxide, the formula of which is SO2, it is tetravalent. In the laboratory, sulfur dioxide is produced in the reaction between sulfate acid and sodium hydrosulfite, the equation of which is
NaHSO3 + H2SO4 → NaHSO4 + SO2 + H2O
Another way to extract SO2 is a redox process between copper and high concentration sulfate acid. The third laboratory method for the production of sulfur oxides is the exhaust combustion of a sample of a simple sulfur substance:
Cu + 2H2SO4=CuSO4 + SO 2 + 2H2O
In industry, sulfur dioxide can be obtained by burning sulfur-containing minerals zinc or lead, as well as by burning pyrite FeS2. The sulfur dioxide obtained by this method is used for the extraction of sulfur trioxide SO3 and further - sulfate acid. Sulfur dioxide with other substances behaves like an oxide with acidic features. For example, its interaction with water leads to the formation of sulfite acid H2SO3:
SO2 + H2O=H2SO 3
This reaction is reversible. The degree of acid dissociation is low, so the compound is classified as a weak electrolyte, and sulfurous acid itself can exist only in an aqueous solution. Sulfur dioxide molecules are always present in it, which give the substance a pungent odor. The reacting mixture is in a state of equal concentration of reactants and products, which can be shifted by changing the conditions. So, when alkali is added to a solution, the reaction will proceed from left to right. If sulfur dioxide is removed from the reaction sphere by heating or blowing through a mixture of gaseous nitrogen, the dynamic equilibrium will shift to the left.
Sulfuric anhydride
Let's continue to consider the properties and methods of obtaining sulfur oxides. If sulfur dioxide is burned, the result is an oxide in which sulfur has an oxidation state of +6. It's sulfur trioxide. The compound is in the liquid phase, quickly hardens in the form of crystals at temperatures below 16 °C. A crystalline substance can be represented by several allotropic modifications that differ in the structure of the crystal lattice and melting points. Sulfuric anhydride exhibits the properties of a reducing agent. Interacting with water, it forms an aerosol of sulfate acid, therefore, in industry, H2SO4 is produced by dissolving sulfuric anhydride in concentrated sulfate acid. As a result, oleum is formed. Adding water to it, and get a solution of sulfuric acid.
Basic oxides
Having studied the properties and production of oxidessulfur, belonging to the group of acidic binary compounds with oxygen, consider the oxygen compounds of metallic elements.
Basic oxides can be determined by such a sign as the presence in the molecules of metal particles of the main subgroups of the first or second groups of the periodic system. They are classified as alkaline or alkaline earth. For example, sodium oxide - Na2O can react with water, resulting in the formation of chemically aggressive hydroxides - alkalis. However, the main chemical property of basic oxides is the interaction with organic or inorganic acids. It goes with the formation of s alt and water. If hydrochloric acid is added to white powdered copper oxide, we will find a bluish-green solution of copper chloride:
CuO + 2HCl=CuCl2 + H2O
Heating solid insoluble hydroxides is another important way to obtain basic oxides:
Ca(OH)2 → CaO + H2O
Conditions: 520-580°C.
In our article, we examined the most important properties of binary compounds with oxygen, as well as methods for obtaining oxides in the laboratory and industry.
