Inorganic acids are very important in the chemical industry. After all, they are the raw material for many syntheses, catalyze processes, act as dewatering agents for dehydration, and so on.
However, their salts are even more valuable - products of the replacement of hydrogen by metal in the composition of their molecules. Carbonic acid is special in this regard. After all, by itself, it practically does not exist, in the air it immediately decays into carbon dioxide and water. But carbonic acid forms salts that have been known to man since ancient times. They are very popular in many areas of production and activity. We will consider them.
Carbonic Acid Salts: Classification
Firstly, it should immediately be indicated that the substances in question can be called in different ways. It just so happened that all the names have taken root and are used to this day, both historically or trivial, as well as data on rational nomenclature. So, salts of carbonic acid, they are called like this:
- carbonates;
- bicarbonates;
- carbonic;
- bicarbonate;
- bicarbonates.
And of course, each one also has its own common name, which is individual.
The above names immediately reflect the classification of the compounds under consideration. Since the acid is dibasic, it forms salts of two types:
Hydro or bi prefixes are added to the name of the latter. Almost every salt of an alkaline or alkaline earth metal is an almost important compound that people need in their business activities.
History of discovery and use
Since ancient times, people have known carbonic acid salts. After all, even in Ancient Egypt, construction was carried out using plaster, alabaster, limestone and marble were used.
In the writings of Pliny the Elder, the technological process of obtaining lime by calcining limestone is mentioned. The famous wonder of the world - the pyramids - was erected using plaster and materials derived from it. Potash was obtained from plant ash and used for washing clothes, and then in soap making.
That is, people always knew how to use products that nature provides. However, the fact that these are salts of carbonic acid, what their structure is, how they can be synthesized artificially, and what their other characteristics are, became known much later, already in the XVII-XVIII centuries.
Today, many carbonates of alkali and alkaline earth metals are also widely used, some of which take an important part in the processes of groundwater circulation.
Deposits in nature
According to the percentage, the considered minerals occupy about 5% of the total mass of the earth's crust. They form mainly on the outside, forming rocks. Also, many salts are formed hydrothermally.
Microorganisms, shellfish and other animals and plants contribute to the formation of carbonates in a biochemical way. Often, salts of carbonic acid are found in ores, accompanying them through the formation of associates.
The most famous minerals and rocks of these compounds:
- calcite;
- dolomite;
- a piece of chalk;
- marble;
- limestone;
- gypsum;
- magnesite;
- siderite;
- malachite.
Methods of preparation and application
Carbonic acid salts are called carbonates (when it comes to medium variations). This means that their composition necessarily includes a carbonate ion, the formula of which is CO 3 2- . To complete the full form of salt, only the metal cation and indices reflecting the quantitative composition of the compound are lacking. It is used in laboratory methods for producing these substances.
Indeed, in addition to extraction from natural sources, carbon salts can also be synthesized by the reactions of exchange, compound and substitution. However, such methods do not have practical significance, since the yield of the product is too small and energy-intensive.
Where is the use of carbonic acid salts carried out, in which areas? For each of them, this is individual, but in general, several main industries can be identified.
- Construction business.
- Chemical industry.
- Glass production.
- Soap making.
- Paper synthesis.
- Food industry.
- Production of detergents and cleaners.
- Calcium carbonates are a source of metal ions in the body of living things.
Let us consider specifically several examples of carbonates, their composition and significance.
Calcium carbonate
As mentioned above, this substance is a source of calcium ions of Ca 2+ in the human body. And this is very important. After all, they take part in maintaining the constancy of the blood buffer system , are part of the bones, nails, hair, and strengthen tooth enamel.
With a lack of calcium, various diseases develop, including such dangerous ones as heart failure, osteoporosis, pathological changes in the lens of the eyeball and others.
In addition, calcium carbonate is also used in the construction industry. After all, its varieties are:
- a piece of chalk;
- marble;
- limestone.
Deposits of this salt are rich enough so that a person does not experience a deficiency in it. Often it is sold in purified form in the form of tablets, as in the photo below. However, for calcium to be absorbed well enough, the presence of vitamin D is required.
Sodium carbonate
Salts of carbonic acid - carbonates - are also important in the household. So, sodium carbonate, or sodium carbonate, in common people has the name soda. However, this is not the substance that is an important part in the preparation of various dishes. No, this salt is used for household purposes for cleaning household surfaces of products: bathtubs, sinks, dishes and others. It is better known as soda ash or linen, it is also used in glass production, soap making.
The formula of this compound is Na 2 CO 3 * 10H 2 O. It is an average aqueous salt related to crystalline hydrates. It is found in nature in the form of minerals and in rocks. Examples:
- the throne;
- nakholit;
- termonatrit.
Often allocated from seaweed, their ash. It was this method that was used in antiquity to obtain raw materials for the production of soap or simply to wash clothes. The richest plant containing this salt is soda water. Its ash is the most acceptable for sodium carbonate.
Potash
The formula for the carbonic acid salt of this name is K 2 CO 3 . This is a white crystalline hygroscopic powder. An average anhydrous salt that has very good solubility. This compound is also known to people for a long time, and it is widely used today. Synonyms for the name:
- potassium carbonate;
- potash;
- potash.
The main areas of use are as follows.
- As a reagent in the production processes of liquid soap.
- For the synthesis of crystal and optical glass, refractory glass.
- For dyeing fabrics.
- As a fertilizer for crops.
- In the construction industry - to reduce the freezing temperature of building mixtures.
- In the photo maker.
The main industrial method for producing this salt is the electrolysis of calcium chloride. In this case, hydroxide is formed, which interacts with carbon dioxide and forms potash. Natural raw materials are ashes of cereals and algae, which contain a lot of it.
Baking soda
Acidic salts of carbonic acid are no less important than the average. So, for example, sodium bicarbonate, the formula of which is NaHCO 3 . Its other name, better known to everyone - is baking soda. Outwardly, it is a white fine powder, which is very soluble in water. The compound is unstable when heated, immediately decomposes into carbon dioxide, water and medium salt. This allows you to use baking soda as a buffer in the internal environment of living organisms.
There are also several other uses of this compound:
- food (especially confectionery) industry;
- medicine (for the treatment of burns with acids);
- in chemical syntheses upon receipt of plastics, dyes, foams, household chemical goods;
- in light and textile industries (tanning of leather, decoration of silk fabrics, etc.);
- used in the manufacture of carbonated drinks and various culinary dishes;
- sodium bicarbonate refuel fire extinguishers.
Calcium bicarbonate
This acidic salt of carbonic acid is an important part in the circulation of groundwater. This compound provides the formation of temporary hardness of water, eliminated by boiling. In this case, it is calcium bicarbonate that contributes to the massive movements of carbonates in nature, that is, it carries out their cycle. The formula of this compound is Ca (HCO 3 ) 2 .